Add Location to RdrName in FieldOcc

Post #11019 (closed), there have been some new instances of RdrName that are not located, in particular

data FieldOcc name = FieldOcc { rdrNameFieldOcc  :: RdrName
                              , selectorFieldOcc :: PostRn name name
                              }

data AmbiguousFieldOcc name
  = Unambiguous RdrName (PostRn name name)
  | Ambiguous   RdrName (PostTc name name)
  deriving (Typeable)

Add locations to them

Trac metadata

Trac field	Value
Version	7.11
Type	Task
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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Differential revisions
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