.rst (restructured text) files freezes the page

[AlexandraVarfolomeyeva37]

Reproduces at the Monaco Editor homepage:
-- https://microsoft.github.io/monaco-editor/
Browser: Edge, Chrome
OS: Windows 10
Playground code that reproduces the issue:
Restructured file:

some property = Text::ProxyLibrary::ProxyInterfaceTest::DeleteProxyInterface();

Causes the UI to become unresponsive or event to freeze and after some time web browser pops up a modal dialog “Page isn’t responding - Wait - Exit Page”.

In a long file, it takes a lot of time to load even if you choose the wait option several times.

[alexdima]

By breaking the JS execution, I could see the tokenizer is stuck on this rule -- https://github.com/microsoft/monaco-languages/blob/319a1ddf568438d59a3851784b092cdf1f88e29e/src/restructuredtext/restructuredtext.ts#L127 . It looks like that particular regular expression is suffering from catastrophic backtracking. cc @qwefgh90

We are more than welcoming a PR by the community!

[qwefgh90]

I will figure out how this bug can be fixed. And there is another rule to freeze the page -- https://github.com/microsoft/monaco-languages/blob/319a1ddf568438d59a3851784b092cdf1f88e29e/src/restructuredtext/restructuredtext.ts#L141.