Fix markdown preview scroll crawls at EOF (fix #249278)

[heoh]

Fix scrolling of markdown preview at EOF. This PR fixes #249278.

• Remove logic that causes scroll errors.

Cause

• At EOF, scroll synchronization is performed every time a character is typed.
• At EOF, the calculated scrollTo is very small, less than 1, but the postprocessing scrolls more than necessary.
  This causes errors again, and to reduce this error, scrollTo is set in the opposite direction again.
• This eventually repeats with every typing, occurs a "crawls" issue.

Resolve

1. First, I removed the logic that causes errors.

2. I checked the history at the time by finding the PR and Issue where the code was written. (457acf8, Fix scrolling of markdown preview. Close #65504 #111094)
   The code was originally written intentionally to fix an old another scrolling issue.
   However, I tested it myself, and the issue that was there before is no longer occurring.

Test

I have tested this PR with the document referenced by previous contributors https://github.com/jlelong/LaTeX-Workshop-wiki/blob/master/Hover.md.

Before

After

Test previous issue

[mjbvz]

Thanks!

[stephenatwork]

Lovely writeup. Thanks @heoh!