Remove broken link and fix markdown formatting

doc/administration/monitoring/performance/request_profiling.md

 # Request Profiling
 
 ## Procedure
+
 1. Grab the profiling token from `Monitoring > Requests Profiles` admin page
-(highlighted in a blue in the image below).
-![Profile token](img/request_profiling_token.png)
-1. Pass the header `X-Profile-Token: <token>` to the request you want to profile. You can use any of these tools
-    * [ModHeader](https://chrome.google.com/webstore/detail/modheader/idgpnmonknjnojddfkpgkljpfnnfcklj) Chrome extension
-    * [Modify Headers](https://addons.mozilla.org/en-US/firefox/addon/modify-headers/) Firefox extension
-    * `curl --header 'X-Profile-Token: <token>' https://gitlab.example.com/group/project`
+  (highlighted in a blue in the image below).
+  ![Profile token](img/request_profiling_token.png)
+1. Pass the header `X-Profile-Token: <token>` to the request you want to profile. You can use:
+    - Browser extensions. For example, [ModHeader](https://chrome.google.com/webstore/detail/modheader/idgpnmonknjnojddfkpgkljpfnnfcklj) Chrome extension.
+    - `curl`. For example, `curl --header 'X-Profile-Token: <token>' https://gitlab.example.com/group/project`.
 1. Once request is finished (which will take a little longer than usual), you can
-view the profiling output from `Monitoring > Requests Profiles` admin page.
-![Profiling output](img/request_profile_result.png)
+  view the profiling output from `Monitoring > Requests Profiles` admin page.
+  ![Profiling output](img/request_profile_result.png)
 
 ## Cleaning up
+
 Profiling output will be cleared out every day via a Sidekiq worker.