PR: Prevent Chinese input method to block edit input area

[ccordoba12]

Description of Changes

• This fix was suggested by a user in The Chinese input method blocks the input content. #23313 but only for the editor. I decided to apply to BaseEditMixin so it also takes effect in the IPython console and other areas where users can edit text.
• Fix some block comments so they appear better in the Outline pane.

Issue(s) Resolved

Fixes #23313

Affirmation

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[ccordoba12]

@meeseeksdev please backport to 6.x

[lumberbot-app]

Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

git checkout 6.x
git pull

2. Cherry pick the first parent branch of the this PR on top of the older branch:

git cherry-pick -x -m1 3f64ee3c2fb7c4ae9af4b9969b66de64d0c3ffe2

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

git commit -am 'Backport PR #23316: PR: Prevent Chinese input method to block edit input area'

4. Push to a named branch:

git push YOURFORK 6.x:auto-backport-of-pr-23316-on-6.x

5. Create a PR against branch 6.x, I would have named this PR:

"Backport PR #23316 on branch 6.x (PR: Prevent Chinese input method to block edit input area)"

And apply the correct labels and milestones.

Congratulations — you did some good work! Hopefully your backport PR will be tested by the continuous integration and merged soon!

Remember to remove the Still Needs Manual Backport label once the PR gets merged.

If these instructions are inaccurate, feel free to suggest an improvement.