350: Super simple macro support r=matklad a=matklad
Super simple support for macros, mostly for figuring out how to fit them into the current architecture. Expansion is hard-coded and string based (mid-term, we should try to copy-paste macro-by-example expander from rustc).
Ideally, we should handle
* highlighting inside the macro (done)
* extend selection inside the macro
* completion inside the macro
* indexing structs, produced by the macro
Co-authored-by: Aleksey Kladov <aleksey.kladov@gmail.com>
7a268b9b96