Implement HLSL syntax highlighting, and use HLSL grammar to highlight Cg blocks in ShaderLab files

Auto-close javadoc

Perform hot exit backup/discard operations in a queue

Fixes #20912

Include newline when expanding line selection

Handle root, network path or disk drive letter

Fix #20897

 Test if git username and password are entered before pushing commit

Fixes issue where whitespace would be eaten in terminal after a link.

See sourcelair/xterm.js#558

Fixes #20797

Related to #20129.

Fixes #7541

* Makes a few TS Extension Types Disposable

**Bug**
TS Extension currently registers many different calls with VSCode but does not handle the disposable result returned from these calls.

**Fix**
For some of these registrations, make sure we correctly dispose of them when the extension is deactivated.

* Fix a few more cases

* Cover a few more case