Updates for tone and style

Revise info provided by Patrick for tone and style. Put more things
in an ordered list. Use the right verb, and end explanations with
colons instead of periods.

doc/user/project/merge_requests/commits.md

@@ -27,7 +27,7 @@ To seamlessly navigate among commits in a merge request:
 
 ![Merge requests commit navigation](img/commit_nav_v13_11.png)
 
-## Merge requests context commits
+## View merge request commits in context
 
 > - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/29274) in GitLab 13.12.
 > - [Deployed behind a feature flag](../../feature_flags.md), enabled by default.
@@ -37,9 +37,9 @@ To seamlessly navigate among commits in a merge request:
 
 WARNING:
 This feature is in [beta](https://about.gitlab.com/handbook/product/gitlab-the-product/#beta)
-and is [**not** complete](https://gitlab.com/groups/gitlab-org/-/epics/1192).
-Previously merged commits can be added but they can't be removed due to [this
-bug](https://gitlab.com/gitlab-org/gitlab/-/issues/325538).
+and is [incomplete](https://gitlab.com/groups/gitlab-org/-/epics/1192).
+Previously merged commits can be added, but they can't be removed due to
+[this bug](https://gitlab.com/gitlab-org/gitlab/-/issues/325538).
 
 This in-development feature might not be available for your use. There can be
 [risks when enabling features still in development](../../feature_flags.md#risks-when-enabling-features-still-in-development).
@@ -51,25 +51,27 @@ that have already merged that the change is built on.
 
 To add previously merged commits to a merge request for more context:
 
+1. Go to your merge request.
 1. Select the **Commits** tab.
-1. Click **Add previously merged commits**.
+1. Scroll to the end of the list of commits, and select **Add previously merged commits**:
 
    ![Add previously merged commits button](img/add_previously_merged_commits_button_v14_1.png)
 
-1. Check the commits that you want to add and click **Save changes**.
+1. Select the commits that you want to add:
 
    ![Add previously merged commits modal](img/add_previously_merged_commits_modal_v14_1.png)
+1. Select **Save changes**.
 
 To view the changes done on those previously merged commits:
 
-1. Select the **Changes** tab.
-1. Compare with **previously merged commits**.
+1. On your merge request, select the **Changes** tab.
+1. Scroll to **(file-tree)** **Compare** and select **previously merged commits**:
 
-![Previously merged commits](img/previously_merged_commits_v14_1.png)
+   ![Previously merged commits](img/previously_merged_commits_v14_1.png)
 
-### Enable or disable merge request context commits **(FREE SELF)**
+### Enable or disable viewing merge request commits in context **(FREE SELF)**
 
-Merge request context commits is under development and not ready for production use. It is
+Viewing merge request commits in context is under development and not ready for production use. It is
 deployed behind a feature flag that is **disabled by default**.
 [GitLab administrators with access to the GitLab Rails console](../../../administration/feature_flags.md)
 can enable it.