Fix package.json Auto complete

Fixes #17906

**bug**
To support completion items that span multiple words, I added extra logic in 1.9 insiders to use the word prefix to compute the completion range. This introduced a few regressions for completions that do start with the replacement.

**fix**
Use the old, word based range logic by default. Use the prefix completion if it is longer.

fixes #17404

[make] Could you add *.mk file extension to be highlighted as a Makefile into default VS Code distribution? Fixes #17734

#16171

#16171

The terminal should be a lot faster at processing output now thanks to
sourcelair/xterm.js#422

Also of note: sourcelair/xterm.js#417: changed escape sequence for alt-arrow to work on bash on os x

#14784

Compute cursor/s state after edits were applied