Update code coverage keyword reference style

doc/ci/yaml/index.md

@@ -3258,15 +3258,16 @@ job:
 
 ### `coverage`
 
-Use `coverage` to configure how code coverage is extracted from the
-job output.
+Use `coverage` with a custom regular expression to configure how code coverage
+is extracted from the job output. The coverage is shown in the UI if at least one
+line in the job output matches the regular expression.
 
-Regular expressions are the only valid kind of value expected here. So, using
-surrounding `/` is mandatory to consistently and explicitly represent
-a regular expression string. You must escape special characters if you want to
-match them literally.
+To extract the code coverage value in the matching line, GitLab uses this
+regular expression: `\d+(\.\d+)?`.
 
-For example:
+**Possible inputs**: A regular expression. Must start and end with `/`.
+
+**Example of `coverage`**:
 
 ```yaml
 job1:
@@ -3274,14 +3275,20 @@ job1:
   coverage: '/Code coverage: \d+\.\d+/'
 ```
 
-The coverage is shown in the UI if at least one line in the job output matches the regular expression.
-If there is more than one matched line in the job output, the last line is used.
-For the matched line, the first occurrence of `\d+(\.\d+)?` is the code coverage.
-Leading zeros are removed.
+In this example:
+
+1. GitLab checks the job log for a line that matches the regular expression. A line
+   like `Code coverage: 67.89` would match.
+1. GitLab then checks the line to find a match to `\d+(\.\d+)?`. The sample matching
+   line above gives a code coverage of `67.89`.
+
+**Additional details**:
 
-Coverage output from [child pipelines](../pipelines/parent_child_pipelines.md) is not recorded
-or displayed. Check [the related issue](https://gitlab.com/gitlab-org/gitlab/-/issues/280818)
-for more details.
+- If there is more than one matched line in the job output, the last line is used.
+- Leading zeros are removed.
+- Coverage output from [child pipelines](../pipelines/parent_child_pipelines.md)
+  is not recorded or displayed. Check [the related issue](https://gitlab.com/gitlab-org/gitlab/-/issues/280818)
+  for more details.
 
 ### `dast_configuration` **(ULTIMATE)**