Fixing typo (singed -> signed); NFC

GitOrigin-RevId: e00071db0854ae9030e3b80a1f82c7cd66d57930
diff --git a/lib/Parse/ParseDecl.cpp b/lib/Parse/ParseDecl.cpp
index 864b7b1..f7d8619 100644
--- a/lib/Parse/ParseDecl.cpp
+++ b/lib/Parse/ParseDecl.cpp
@@ -2742,7 +2742,7 @@
     default:
       // This is probably supposed to be a type. This includes cases like:
       //   int f(itn);
-      //   struct S { unsinged : 4; };
+      //   struct S { unsigned : 4; };
       break;
     }
   }