Add language declarations to various code blocks

This MR adds language declarations to several pages in the /user
subdirectory.

doc/user/markdown.md

@@ -581,7 +581,7 @@ Quote break.
 GFM extends the standard Markdown standard by also supporting multiline blockquotes
 fenced by `>>>`:
 
-```
+```markdown
 >>>
 If you paste a message from somewhere else
 
@@ -630,7 +630,7 @@ def function():
     3-backtick fences.
 ~~~
 
-```
+```plaintext
 ~~~
 Tildes are OK too.
 ~~~
@@ -638,20 +638,20 @@ Tildes are OK too.
 
 The three examples above render as:
 
-```
+```python
 def function():
     #indenting works just fine in the fenced code block
     s = "Python code"
     print s
 ```
 
-```
+```plaintext
 Using 4 spaces
 is like using
 3-backtick fences.
 ```
 
-~~~
+~~~plaintext
 Tildes are OK too.
 ~~~
 
@@ -668,7 +668,7 @@ code when it is inline.
 Blocks of code are fenced by lines with three back-ticks ```` ``` ```` or three tildes `~~~`, and have
 the language identified at the end of the first fence:
 
-~~~
+~~~markdown
 ```javascript
 var s = "JavaScript syntax highlighting";
 alert(s);
@@ -714,7 +714,7 @@ markdown = Redcarpet.new("Hello World!")
 puts markdown.to_html
 ```
 
-```
+```plaintext
 No language indicated, so no syntax highlighting.
 s = "There is no highlighting for this."
 But let's throw in a <b>tag</b>.
@@ -756,7 +756,7 @@ dealing with code and names that often appear with multiple underscores. As a re
 GFM extends the standard Markdown standard by ignoring multiple underlines in words,
 to allow better rendering of Markdown documents discussing code:
 
-```md
+```markdown
 perform_complicated_task
 
 do_this_and_do_that_and_another_thing
@@ -852,7 +852,7 @@ The IDs are generated from the content of the header according to the following
 
 Example:
 
-```
+```markdown
 # This header has spaces in it
 ## This header has a :thumbsup: in it
 # This header has Unicode in it: 한글
@@ -1148,7 +1148,7 @@ A new line due to the previous backslash.
 
 There are two ways to create links, inline-style and reference-style:
 
-```md
+```markdown
 - This is an [inline-style link](https://www.google.com)
 - This is a [link to a repository file in the same directory](index.md)
 - This is a [relative link to a readme one directory higher](../README.md)
@@ -1319,7 +1319,7 @@ the paragraph will appear outside the list, instead of properly indented under t
 
 Example:
 
-```
+```markdown
 1. First ordered list item
 
   Paragraph of first item.

doc/user/packages/conan_repository/index.md

@@ -39,7 +39,7 @@ conan --version
 
 You should see the Conan version printed in the output:
 
-```
+```plaintext
 Conan version 1.20.5
 ```
 

doc/user/packages/npm_registry/index.md

@@ -49,7 +49,7 @@ npm --version
 
 You should see the NPM version printed in the output:
 
-```
+```plaintext
 6.10.3
 ```
 
@@ -67,7 +67,7 @@ yarn --version
 
 You should see the version printed like so:
 
-```
+```plaintext
 1.19.1
 ```
 

doc/user/packages/nuget_repository/index.md

@@ -26,7 +26,7 @@ nuget help
 
 You should see something similar to:
 
-```
+```plaintext
 NuGet Version: 5.2.0.6090
 usage: NuGet <command> [args] [options]
 Type 'NuGet help <command>' for help on a specific command.

doc/user/project/description_templates.md

@@ -91,7 +91,7 @@ It is possible to use [quick actions](quick_actions.md) within description templ
 
 Here is an example for a Bug report template:
 
-```
+```plaintext
 Summary
 
 (Summarize the bug encountered concisely)

doc/user/project/integrations/gitlab_slack_application.md

@@ -56,7 +56,7 @@ We are working on making this configurable in the future.
 For example, to show the issue number `1001` under the `gitlab-org/gitlab`
 project, you would do:
 
-```
+```plaintext
 /gitlab gitlab-org/gitlab issue show 1001
 ```
 

doc/user/project/integrations/hipchat.md

@@ -25,7 +25,7 @@ allow GitLab to send messages only to *one* room.
 1. In the "Send messages to this room by posting this URL" column, you should
    see a URL in the format:
 
-```
+```plaintext
 https://api.hipchat.com/v2/room/<room>/notification?auth_token=<token>
 ```
 

doc/user/project/integrations/irker.md

@@ -11,7 +11,7 @@ See the project homepage for further info: <https://gitlab.com/esr/irker>
 You will first need an Irker daemon. You can download the Irker code from its
 repository on <https://gitlab.com/esr/irker>:
 
-```
+```shell
 git clone https://gitlab.com/esr/irker.git
 ```
 

doc/user/project/integrations/jira.md

@@ -119,7 +119,7 @@ link back to GitLab. This means that in comments in merge requests and commits
 referencing an issue, e.g., `PROJECT-7`, will add a comment in Jira issue in the
 format:
 
-```
+```plaintext
 USER mentioned this issue in RESOURCE_NAME of [PROJECT_NAME|LINK_TO_COMMENT]:
 ENTITY_TITLE
 ```

doc/user/project/integrations/prometheus_library/kubernetes.md

@@ -13,13 +13,13 @@ integration services must be enabled.
 
 - Average Memory Usage (MB):
 
-  ```
+  ```prometheus
   avg(sum(container_memory_usage_bytes{container_name!="POD",pod_name=~"^%{ci_environment_slug}-([^c].*|c([^a]|a([^n]|n([^a]|a([^r]|r[^y])))).*|)-(.*)",namespace="%{kube_namespace}"}) by (job)) without (job) / count(avg(container_memory_usage_bytes{container_name!="POD",pod_name=~"^%{ci_environment_slug}-([^c].*|c([^a]|a([^n]|n([^a]|a([^r]|r[^y])))).*|)-(.*)",namespace="%{kube_namespace}"}) without (job)) /1024/1024
   ```
 
 - Average CPU Utilization (%):
 
-  ```
+  ```prometheus
   avg(sum(rate(container_cpu_usage_seconds_total{container_name!="POD",pod_name=~"^%{ci_environment_slug}-([^c].*|c([^a]|a([^n]|n([^a]|a([^r]|r[^y])))).*|)-(.*)",namespace="%{kube_namespace}"}[15m])) by (job)) without (job) / count(sum(rate(container_cpu_usage_seconds_total{container_name!="POD",pod_name=~"^%{ci_environment_slug}-([^c].*|c([^a]|a([^n]|n([^a]|a([^r]|r[^y])))).*|)-(.*)",namespace="%{kube_namespace}"}[15m])) by (pod_name))
   ```
 
@@ -48,12 +48,12 @@ These metrics expect the [Deployment](https://kubernetes.io/docs/concepts/worklo
 
 - Average Memory Usage (MB)
 
-  ```
+  ```prometheus
   avg(sum(container_memory_usage_bytes{container_name!="POD",pod_name=~"^%{ci_environment_slug}-canary-(.*)",namespace="%{kube_namespace}"}) by (job)) without (job) / count(avg(container_memory_usage_bytes{container_name!="POD",pod_name=~"^%{ci_environment_slug}-canary-(.*)",namespace="%{kube_namespace}"}) without (job)) /1024/1024
   ```
 
 - Average CPU Utilization (%)
 
-  ```
+  ```prometheus
   avg(sum(rate(container_cpu_usage_seconds_total{container_name!="POD",pod_name=~"^%{ci_environment_slug}-canary-(.*)",namespace="%{kube_namespace}"}[15m])) by (job)) without (job) / count(sum(rate(container_cpu_usage_seconds_total{container_name!="POD",pod_name=~"^%{ci_environment_slug}-canary-(.*)",namespace="%{kube_namespace}"}[15m])) by (pod_name))
   ```

doc/user/project/new_ci_build_permissions_model.md

@@ -101,14 +101,14 @@ allowing pulling and pushing Docker images from within the CI job.
 
 GitLab would create a special checkout URL like:
 
-```
+```plaintext
 https://gitlab-ci-token:<project-runners-token>/gitlab.com/gitlab-org/gitlab-foss.git
 ```
 
 And then the users could also use it in their CI jobs all Docker related
 commands to interact with GitLab Container Registry. For example:
 
-```
+```shell
 docker login -u gitlab-ci-token -p $CI_JOB_TOKEN registry.gitlab.com
 ```
 
@@ -173,14 +173,14 @@ As a user:
 The [Job environment variable][jobenv] `CI_JOB_TOKEN` can be used to
 authenticate any clones of dependent repositories. For example:
 
-```
+```shell
 git clone https://gitlab-ci-token:${CI_JOB_TOKEN}@gitlab.com/<user>/<mydependentrepo>.git
 ```
 
 It can also be used for system-wide authentication
 (only do this in a docker container, it will overwrite ~/.netrc):
 
-```
+```shell
 echo -e "machine gitlab.com\nlogin gitlab-ci-token\npassword ${CI_JOB_TOKEN}" > ~/.netrc
 ```