Use text.html.erb scope for HTML+ERB files

This grammar does a better job highlighting than the text.html.ruby grammar does. It requires injection grammar support, but there's no getting around that.
Merge pull request #1641 from github/aroben-patch-1

Use text.html.erb scope for HTML+ERB files
Bumping version for 3.4.1 release
Merge pull request #1643 from github/linguist-3.4.1

Bumping version for 3.4.1 release
Add moon interpreter for MoonScript
Merge pull request #1645 from pchaigno/moon-shebang

Add moon interpreter for MoonScript
Update README.md
Removing stale extension
Merge pull request #1646 from github/gradle-extension

Removing stale extension
Add a multitude of Forth file extensions.
Yes, these are all in use.
Make test_pedantic accept quotes around extensions.