Support auto-format for tree-sitter injections

[nik-rev]

Currently, when automatically formatting files with auto-format tree-sitter injections are not formatted.
It would be useful to have this feature primarily for working with markdown (and similar markup languages) where we can have many code blocks

Right now if you want to format those code blocks you have to use :pipe rustfmt for instance. Having auto-formatting for them would be quite useful.

as pointed out in #9425 (comment) this may not be possible to implement or very hard:

not quite sure if this is even feasible. For combined injections the formatter may only be able to handle the full combined text as valid syntax but it's hard/impossible to map that back to the original ranges.

It would also take a lot of.reaources as we would habe tu run O(N*maxdepth) parses + queries and formatter invocations

if implemented it should be opt-in (such as having format-injections options per-language and globally)