Document enhancements to MR Analytics

Recently there were multiple enhancements to the MR Analytics feature:
date range customization, deep linking, pagination and displaying
approval count. This adds documentation for all of these enhancements.

doc/user/analytics/merge_request_analytics.md

@@ -36,7 +36,7 @@ Merge Request Analytics could be used when:
 
 ## Visualizations and data
 
-The following visualizations and data are available, representing all merge requests that were merged in the past 12 months.
+The following visualizations and data are available, representing all merge requests that were merged in the given date range.
 
 ### Throughput chart
 
@@ -46,7 +46,25 @@ The throughput chart shows the number of merge requests merged per month.
 
 ### Throughput table
 
-Data table displaying a maximum of the 100 most recent merge requests merged for the time period.
+[Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/232651) in GitLab 13.3.
+
+The Throughput table displays the most recent merge requests merged in the date range. The
+table displays up to 20 merge requests at a time. If there are more than 20 merge requests,
+you can paginate to them. For each merge request, you can review the following data:
+
+- Title (as a link to the merge request itself)
+- ID
+- Pipeline status
+- Label count
+- Comment count
+- Approval count (if approved)
+- Date merged
+- Time to merge
+- Milestone
+- Commit count
+- Pipeline count
+- Line change counts
+- Assignees
 
 ![Throughput table](img/mr_throughput_table_v13_3.png "Merge Request Analytics - Throughput table listing the 100 merge requests most recently merged")
 
@@ -68,6 +86,17 @@ To filter results:
 1. Click on the filter bar.
 1. Select a parameter to filter by.
 1. Select a value from the autocompleted results, or enter search text to refine the results.
+1. Hit the "Return" key.
+
+## Date range
+
+The date range is set to the past 12 months by default. You can modify the date range by changing the "From" and/or "To" values that appear alongside the filter bar. After changing either value, the data displayed on the page will update automatically.
+
+## Tip: Bookmark preferred settings
+
+You can bookmark preferred filters and date ranges. After you have applied a change to the
+filter bar or the date range, you'll see that information in the URL. You can create a
+bookmark for those preferred settings in your browser.
 
 ## Permissions