EPA: cleanups after the merge

Remove EpaAnn type synonym, rename EpaAnn' to EpaAnn.
Closes #19705

Updates haddock submodule

--

Change
  data EpaAnchor = AR RealSrcSpan
                 | AD DeltaPos

To instead be
  data EpaAnchor = AnchorReal RealSrcSpan
                 | AnchorDelta DeltaPos

Closes #19699

--

Change
  data DeltaPos =
    DP
      { deltaLine   :: !Int,
        deltaColumn :: !Int
      }

To instead be
  data DeltaPos
    = SameLine { deltaColumn :: !Int }
    | DifferentLine { deltaLine :: !Int, startColumn :: !Int }

Closes #19698

--

Also some clean-ups of unused parts of check-exact.