Re-accept baseline after switch to explicit | undefined

Author: sjbarag

tests/baselines/reference/api/tsserverlibrary.d.ts

@@ -3794,7 +3794,7 @@ declare namespace ts {
         getEscapedName(): __String;
         getName(): string;
         getDeclarations(): Declaration[] | undefined;
-        getDocumentationComment(typeChecker?: TypeChecker): SymbolDisplayPart[];
+        getDocumentationComment(typeChecker: TypeChecker | undefined): SymbolDisplayPart[];
         getJsDocTags(): JSDocTagInfo[];
     }
     interface Type {
@@ -3815,7 +3815,7 @@ declare namespace ts {
         getTypeParameters(): TypeParameter[] | undefined;
         getParameters(): Symbol[];
         getReturnType(): Type;
-        getDocumentationComment(typeChecker?: TypeChecker): SymbolDisplayPart[];
+        getDocumentationComment(typeChecker: TypeChecker | undefined): SymbolDisplayPart[];
         getJsDocTags(): JSDocTagInfo[];
     }
     interface SourceFile {