feat(rome-formatter): Comments Map

This PR implements a multimap for storing the leading, dangling, and trailing comments for nodes.

An implementation using a general-purpose implementation would use a multimaps for the leading, trailing, and dangling comments and
 each multimap would allocate a `Vec` for every node with a comment.

 This purpose-built multimap uses a shared `Vec` to store all comments where this is possible (99.99% of comments) and only allocates
 node specific `Vec`s if necessary.

The idea behind the implementation is that comments should maintain the same order as in the source document. That means:
* All comments for a node are inserted at "the same" time (one at a time, but all together)
* It first inserts the leading, then dangling, and finally, a node's trailing comments.

crates/rome_formatter/Cargo.toml

@@ -16,6 +16,7 @@ cfg-if = "1.0.0"
 indexmap = "1.8.2"
 schemars = { version = "0.8.10", optional = true }
 rustc-hash = "1.1.0"
+countme = "3.0.1"
 
 [features]
 serde = ["dep:serde", "schemars", "rome_rowan/serde"]

crates/rome_formatter/src/comments.rs

@@ -1,3 +1,5 @@
+mod map;
+
 use rome_rowan::{
     Direction, Language, SyntaxElement, SyntaxKind, SyntaxNode, SyntaxTriviaPieceComments,
     WalkEvent,