Use standard injection.language and injection.content captures (#22268)

Closes #9656. Continuation of #9654, but with the addition of backwards
compatibility for the existing captures.

Release Notes:

- Improved Tree-sitter support with added compatibility for standard
injections captures

---------

Co-authored-by: Finn Evers <finn.evers@outlook.de>

crates/outline_panel/src/outline_panel.rs

@@ -6043,8 +6043,8 @@ mod tests {
         .with_injection_query(
             r#"
                 (macro_invocation
-                    (token_tree) @content
-                    (#set! "language" "rust"))
+                    (token_tree) @injection.content
+                    (#set! injection.language "rust"))
             "#,
         )
         .unwrap()