Document reference highlighting mod

crates/ide/src/syntax_highlighting.rs

@@ -138,8 +138,9 @@ pub struct HlRange {
 // injected:: Emitted for doc-string injected highlighting like rust source blocks in documentation.
 // intraDocLink:: Emitted for intra doc links in doc-strings.
 // library:: Emitted for items that are defined outside of the current crate.
+// mutable:: Emitted for mutable locals and statics as well as functions taking `&mut self`.
 // public:: Emitted for items that are from the current crate and are `pub`.
-// mutable:: Emitted for mutable locals and statics.
+// reference: Emitted for locals behind a reference and functions taking `self` by reference.
 // static:: Emitted for "static" functions, also known as functions that do not take a `self` param, as well as statics and consts.
 // trait:: Emitted for associated trait items.
 // unsafe:: Emitted for unsafe operations, like unsafe function calls, as well as the `unsafe` token.