Fix prepending unused TypeScript variables with underscore doesn't rename JSDoc @param.

Fix test for quick fix "Prefix all unused declarations with '_' where possible".
Fixes microsoft#33021.

Author: sergeir82

src/services/codefixes/fixUnusedIdentifier.ts

@@ -60,7 +60,7 @@ namespace ts.codefix {
                 }
             }
 
-            const prefix = textChanges.ChangeTracker.with(context, t => tryPrefixDeclaration(t, errorCode, sourceFile, token));
+            const prefix = textChanges.ChangeTracker.with(context, t => tryPrefixDeclaration(t, errorCode, sourceFile, checker, token));
             if (prefix.length) {
                 result.push(createCodeFixAction(fixName, prefix, [Diagnostics.Prefix_0_with_an_underscore, token.getText(sourceFile)], fixIdPrefix, Diagnostics.Prefix_all_unused_declarations_with_where_possible));
             }
@@ -76,7 +76,7 @@ namespace ts.codefix {
                 const token = getTokenAtPosition(sourceFile, diag.start);
                 switch (context.fixId) {
                     case fixIdPrefix:
-                        tryPrefixDeclaration(changes, diag.code, sourceFile, token);
+                        tryPrefixDeclaration(changes, diag.code, sourceFile, checker, token);
                         break;
                     case fixIdDelete: {
                         if (token.kind === SyntaxKind.InferKeyword) break; // Can't delete
@@ -146,14 +146,19 @@ namespace ts.codefix {
         return false;
     }
 
-    function tryPrefixDeclaration(changes: textChanges.ChangeTracker, errorCode: number, sourceFile: SourceFile, token: Node): void {
+    function tryPrefixDeclaration(changes: textChanges.ChangeTracker, errorCode: number, sourceFile: SourceFile, checker: TypeChecker, token: Node): void {
         // Don't offer to prefix a property.
         if (errorCode === Diagnostics.Property_0_is_declared_but_its_value_is_never_read.code) return;
         if (token.kind === SyntaxKind.InferKeyword) {
             token = cast(token.parent, isInferTypeNode).typeParameter.name;
         }
         if (isIdentifier(token) && canPrefix(token)) {
             changes.replaceNode(sourceFile, token, createIdentifier(`_${token.text}`));
+            FindAllReferences.Core.eachSymbolReferenceInFile(token, checker, sourceFile, (ref: Node) => {
+                if (isIdentifier(ref)) {
+                    changes.replaceNode(sourceFile, ref, createIdentifier(`_${ref.text}`));
+                }
+            });
         }
     }
 

tests/cases/fourslash/codeFixUnusedIdentifier_all_prefix.ts

@@ -3,6 +3,10 @@
 // @noUnusedLocals: true
 // @noUnusedParameters: true
 
+/////**
+//// * @param a First parameter.
+//// * @param b Second parameter.
+//// */ 
 ////function f(a, b) {
 ////    const x = 0; // Can't be prefixed, ignored
 ////}
@@ -12,7 +16,11 @@ verify.codeFixAll({
     fixId: "unusedIdentifier_prefix",
     fixAllDescription: "Prefix all unused declarations with '_' where possible",
     newFileContent:
-`function f(_a, _b) {
+`/**
+ * @param _a First parameter.
+ * @param _b Second parameter.
+ */ 
+function f(_a, _b) {
     const x = 0; // Can't be prefixed, ignored
 }
 type Length<T> = T extends ArrayLike<infer _U> ? number : never;`,