Add support for Rust Analyzer

[londospark]

Would it be possible to add support for the kinds of macro that can be parsed by syn-rsx to rust analyzer to give a better IDE experience?

[vldm]

Hi, i am working on my fork of syn-rsx, with aim to this feature. Could you please provide more info to the issue (maybe some screenshots from macro usage), so i can check is it already work on my fork, as it expected.

Example of completely broken rust+html syntax (unparsable expressions, broken tags) that still provide basic support of ra:

1. completion
2. symantic highlight

In terminal it also provide note to make errors more clear