Update pull request commenting instructions and screenshot

[ashis-baral]

Why:

fix: #45814

What's being changed (if available, include any code snippets, screenshots, or gifs):

This PR updates the pull request commenting documentation to match the current GitHub UI.

The following changes are being made:

• Update Add single comment to Comment because the current UI uses the Comment button when submitting an individual comment.

• Update Finish your review to Submit review to match the current UI.

• Update the outdated screenshot. The current screenshot shows the old Add a single comment button, while the current GitHub UI shows Comment.

Check off the following:

• A subject matter expert (SME) has reviewed the technical accuracy of the content in this PR. In most cases, the author can be the SME. Open source contributions may require an SME review from GitHub staff.
• The changes in this PR meet the docs fundamentals that are required for all content.
• All CI checks are passing and the changes look good in the review environment.

[github-actions]

How to review these changes 👓

Thank you for your contribution. To review these changes, choose one of the following options:

• Spin up a codespace
• Set up a local development environment

A Hubber will need to deploy your changes internally to review.

Table of review links

Note: Please update the URL for your staging server or codespace.

The table shows the files in the content directory that were changed in this pull request. This helps you review your changes on a staging server. Changes to the data directory are not included in this table.

Source	Review	Production	What Changed
pull-requests/how-tos/review-pull-requests/commenting-on-a-pull-request.md	fpt ghec ghes@ 3.22 3.21 3.20 3.19 3.18 3.17	fpt ghec ghes@ 3.22 3.21 3.20 3.19 3.18 3.17

Key: fpt: Free, Pro, Team; ghec: GitHub Enterprise Cloud; ghes: GitHub Enterprise Server

🤖 This comment is automatically generated.

[subatoi]

Hi again @ashis-baral, your changes are correct for FPT/GHEC, but the original text is still true for GHES. Would you be OK adding versioning to that effect? Many thanks