Add public semantic token modifier for public items

crates/rust-analyzer/src/to_proto.rs

@@ -505,6 +505,7 @@ fn semantic_token_type_and_modifiers(
             HlMod::Consuming => semantic_tokens::CONSUMING,
             HlMod::Async => semantic_tokens::ASYNC,
             HlMod::Library => semantic_tokens::LIBRARY,
+            HlMod::Public => semantic_tokens::PUBLIC,
             HlMod::Unsafe => semantic_tokens::UNSAFE,
             HlMod::Callable => semantic_tokens::CALLABLE,
             HlMod::Static => lsp_types::SemanticTokenModifier::STATIC,