Update to Scintilla5 (#2867)

Update to Scintilla5  (#2867)

* Update Scintilla to version 5.1.1

A few notes:
- C++17 is required
  Not exactly new since we already imported the latest julia lexer.
- upstream split out lexers into a lexilla library
  We do "comply" by building a separate static library. So in effect, all
  lexers are built-in like before. In the future it may be possible to add
  lexer plugins at runtime.
- Lexer IDs are deprecated in favor of names
  For now we use LexerNameFromID() to map IDs to names but we should
  transition to names soon.
  That being said, the upstream transition seems also not complete.
  There is no name-based version of SCI_GETLEXER, so we're stuck with IDs
  there.

Closes #2824

* Update scintilla_changes.patch

The "which lexers" part is now a separate function that should be less
of a pain when updating to scintilla version that adds lexers.

* Update update-scintilla.sh

You need to extract lexilla sources too now and pass it to the script.
Also the script calls dos2unix for the files, kill that CRLF!