Syntax highlighting in Azure Devops PR

[serbrech]

Now that typespec standardized on its new name and file extension, could we have syntax highlighting in Azure Devops?
reviewing PRs is much harder without it, even more relevant for a syntax that is going to be new to many developers.

Typespec can be a fraction of the size of swagger, it is still easier to review json highlighted than typespec in monochrome.
Even a browser extension would make me happy.

[timotheeguerin]

For this to be possible I belive the steps are:

1. Add the language tokenizer to monaco-editor
   2.Work with Azure Devops team so they pull in the new changes

[timotheeguerin]

PR for the first step microsoft/monaco-editor#4450