EPA: Replace Anchor with EpaLocation
An Anchor has a location and an operation, which is either that it is
unchanged or that it has moved with a DeltaPos
data Anchor = Anchor { anchor :: RealSrcSpan
, anchor_op :: AnchorOperation }
An `EpaLocation` also has either a location or a `DeltaPos`
```hs
data EpaLocation = EpaSpan !RealSrcSpan !(Strict.Maybe BufSpan)
| EpaDelta !DeltaPos ![LEpaComment]
Now that we do not care about always having a location in the anchor,
we remove Anchor
and replace it with EpaLocation
We do this with a type alias initially, to ease the transition. The alias will be removed in time.
We also have helpers to reconstruct the AnchorOperation
from an
EpaLocation
. This is also temporary.
Updates Haddock submodule