Update quick action help text

What does this MR do and why?

Illustrates how to use quick actions in a comment but adjusting the help text.

Closes #356715 (closed)

Screenshots or screen recordings

No quick actions

Before	After
Wiki - Vue	Wiki - Vue
Snippets - Haml	Snippets - Haml

Both Markdown and quick actions

Before	After
Incidents - Vue	Incidents - Vue
Commits - Haml	Commits - Haml

Haml changes

How to set up and validate locally

For Vue changes

1. Navigate to Wiki page edit to examine toolbar with no quick action support
2. Navigate to an Incident, Issue, or Merge request to examine the toolbar both Markdown and quick actions

For Haml changes

1. Navigate to a Snippet to examine toolbar with no quick action support
2. Navigate to a Commit to examine to examine the toolbar with both Markdown and quick actions

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.