Smarter line clipping in Find in Files

[marcelgerber]

For #9659 (at least part of it).
Best to explain with a before/after:
Before:

After:

So there are three ways text can clip:

• If endCh (last char of match) is < 200, the line is simply displayed and clipped after 200 chars
• If the match is longer than 200 chars, the match is displayed, highlighted and clipped after 200 chars (may not be perfect, but you'll probably only get into this state with RegExps)
• Else, the code tries to center the match in the displayed line (and, of course, it highlights the match)

[peterflynn]

@marcelgerber I think this might run into some bugs with matches that span multiple lines. The code here still assumes the start ch is on the first line of the match and the end ch is on the last, which might be incorrect depending on which clipping case you fall into. This was already somewhat buggy before your change, so it may not be an urgent issue... but just fyi. In case you feel like doing any more work on this code :-)

Also, might not hurt to add some clipping tests to FindInFiles-test at some point.

[peterflynn]

Sorry, that comment should be attached to the line.substr()/.substring() calls, not the end: initializer here...

[marcelgerber]

Multi-line results are automatically being trimmed, so this shouldn't be a problem.