Limit search response size to avoid crash/perf issues

[MinusGix]

• Added an entry to CHANGELOG.md if this change could be valuable to users

There was a bug where searching in a workspace with files with large one-liner text would cause the editor to die (sometimes crash, sometimes visual artifacts due to creating a too large text layout and maybe messing with GPU memory or something). A common example would be minified javascript files, which are on a singular line and are quite massive.
The issue was that the search would respond with the entire line's text, which could be a lot (ex: one of my files was 500kb of text in a single line)! This wouldn't be too bad by itself, though it would probably stress search performance if you had a lot of them, but the main issue comes from trying to render it. It would try creating a text layout, which would then cause issues due to it being so large.

The fix is just to take a part of the line, 100 characters before and 100 characters after the end of the match, and restrict the text sent (and thus displayed) to that.

[codecov-commenter]

Codecov Report

Merging #1753 (eb7af1a) into master (4be5347) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

@@            Coverage Diff            @@
##           master   #1753      +/-   ##
=========================================
- Coverage    6.54%   6.54%   -0.01%     
=========================================
  Files         127     127              
  Lines       54089   54100      +11     
=========================================
  Hits         3541    3541              
- Misses      50548   50559      +11     

Impacted Files	Coverage Δ
lapce-proxy/src/dispatch.rs	0.00% <0.00%> (ø)

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