Added support for Rust

[marcolgl]

Hi, i wrote two functions to support folding in Rust. In particular the following tree-sitter-node-types are folded:

• struct_item
• enum_item
• function_item
• impl_item
• mod_item
• match_expression match in Rust is a ExpressionWithBlock, it can be followed by a semicolon or not depending on what we want to do with its return value. Then semicolon is not folded to make it explicit its presence and role even when then match item is folded
• macro_definition this required its own function because the nodes to match have a slightly different pattern in the grammar

I added two entries in tree-sitter-foldable-node-alist and tree-sitter-fold-range-alist because there are currently (as far as i know) two major mode for rust: rust-mode and rustic-mode . That is redundant but makes folding work in both cases.

I am very new to elisp, so corrections and suggestions are welcome. Thanks for reading and for the work on this package

[junyi-hou]

sorry I was slow to respond, let me check it this week and hopefully merge this. Thanks!

[marcolgl]

No worries, take all the time you need. In the last commit I added two other node-types:

• trait_item
• macro_invocation