Added common alternative Handlebars extensions
Needed handlebars extensions in alpha-numeric order.
Add LaTeX and BibTeX
Update languages.yml
Update languages.yml
Add definitions to TeX
TypeScript: fixed syntax, it wasn't TypeScript at all
Highlight .jelly files as XML

[Jelly](http://commons.apache.org/proper/commons-jelly/) is used heavily by stapler/stapler and jenkinsci/jenkins.
Merge pull request #701 from thorn0/patch-1

TypeScript: fixed syntax, it wasn't TypeScript at all
Merge pull request #721 from olivergondza/patch-1

Highlight .jelly files as XML
Merge pull request #663 from acgetchell/patch-2

Add LaTeX and BibTeX
Merge pull request #584 from jayphelps/patch-1

Added common alternative Handlebars extensions