Allow keywords which can be used as variables to be used with OverloadedDotSyntax

There are quite a few keywords which are allowed to be used as
variables. Such as "as", "dependency" etc. These weren't accepted by
OverloadedDotSyntax.

The fix is pretty simple, use the varid production rather than raw
VARID.

Fixes #20723

compiler/GHC/Parser.y

@@ -3720,7 +3720,7 @@ qvar    :: { LocatedN RdrName }
 -- *after* we see the close paren.
 
 field :: { Located FastString  }
-      : VARID { sL1 $1 $! getVARID $1 }
+      : varid { reLocN $ fmap (occNameFS . rdrNameOcc) $1 }
 
 qvarid :: { LocatedN RdrName }
         : varid               { $1 }

testsuite/tests/overloadedrecflds/should_compile/T20723.hs

+{-# LANGUAGE OverloadedRecordDot #-}
+module T20723 where
+
+data Rec = Rec { as :: Int, dependency :: Int, signature :: Int, javascript :: Int }
+
+res r = r.as + r.dependency + r.signature + r.javascript
+
+
+

testsuite/tests/overloadedrecflds/should_compile/all.T

@@ -9,4 +9,5 @@ test('NFSImport', [extra_files(['NFSExport.hs'])], multimod_compile, ['NFSImport
 test('T18999_NoFieldSelectors', normal, compile, [''])
 test('T18999_FieldSelectors', normal, compile, [''])
 test('T19154', normal, compile, [''])
+test('T20723', normal, compile, [''])