One big cleanup pass of clippy lints

Co-authored-by: Mikayla <mikayla@zed.dev>

crates/zed/src/languages/c.rs

@@ -116,7 +116,7 @@ impl super::LspAdapter for CLspAdapter {
     ) -> Option<CodeLabel> {
         let label = completion
             .label
-            .strip_prefix("•")
+            .strip_prefix('•')
             .unwrap_or(&completion.label)
             .trim();