Handle OnEnterRule patterns

[gbodeen]

What it does

Fixes #12217 and the issue raised in #12212 .

The format of OnEnterRule had been defined with beforeText, afterText, and previousLineText as only strings. However they are often quasi-RegExp objects with pattern and flags string fields.

How to test

1. With TypeScript plugins 1.66.2 or later, in a JavaScript or TypeScript file, if you hit Enter to create a new line, do you still get * appended inappropriately?
2. Similarly in HTML files, if you hit Enter to create a new line, do you still get two new lines inappropriately?
3. Do other insertions (e.g. for JsDoc strings) still work properly?

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Note: I've only tested on RHEL7, electron & browser modes, and a limited set of circumstances involving insertions of newlines.

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[colin-grant-work]

These changes address the problems previously observed with recent language feature plugins. 👍

[vince-fugnitto]

LGTM 👍
I confirmed that:

• the onEnterRule are properly applied (ex: comments)
• we no longer get the odd behavior for HTML, or TypeScript for newlines

[ccorn]

This means that 2f287df can be reverted, right?

[vince-fugnitto]

@ccorn the changes already remove the pinned builtins:

https://github.com/eclipse-theia/theia/pull/12228/files#diff-7ae45ad102eab3b6d7e7896acd08c427a9b25b346470d7bc6507b6481575d519L106-R106