The current positionmappings is composing in the wrong way in lastValueIO

[soulomoon]

I discover the problem when developing Semantic tokens

          I observed a bizzared behaviour when using possition mappings
          in vscode.
          in the first 6 space insert, the using possition mapping to ident the code seems to be working,
          Then the column at the start position stop to update
          ```
          Range {_start = Position {_line = 139, _character = 16}, _end = Position {_line = 139, _character = 25}} spanNames_atz7
          Range {_start = Position {_line = 139, _character = 17}, _end = Position {_line = 139, _character = 26}} spanNames_atz7
          Range {_start = Position {_line = 139, _character = 17}, _end = Position {_line = 139, _character = 27}} spanNames_atz7
          ```
          
          <img width="259" alt="Screenshot 2023-12-23 at 13 19 25" src="https://github.com/haskell/haskell-language-server/assets/14073857/3e98cb7f-9f45-4c60-a37a-e499b3cca129">
          
          here is another one
          ```
          Range {_start = Position {_line = 25, _character = 13}, _end = Position {_line = 25, _character = 19}} xxxxx_aTsW
          Range {_start = Position {_line = 25, _character = 13}, _end = Position {_line = 25, _character = 20}} xxxxx_aTsW
          # with
          [TextDocumentContentChangeEvent (InL (#range .== Range {_start = Position {_line = 25, _character = 9}, _end = Position {_line = 25, _character = 9}} .+ #rangeLength .== Just 0 .+ #text .== " "))]
          ```

Originally posted by @soulomoon in #3892 (comment)
When useWithStale, the old delta is mistakenly be considered as new.
I will open a pull request to fix this.

[soulomoon]

Actually the error happens on the 6th insertions. Just not visible.

The behaviour is subtle on just inserting spaces consistantly:
say the each insertion of whitespace at left of the following.
(x, y), (x+1, y), , (x+2, y) ...
the code let spanNames start at (x,y), notice spanNames start at (x+5). (Suppose this is what the stale version is)
the code after 5 insertions is let spanNames start at (x+5,y). Notice spanNames moves from the stale version
from x+5 to x+10 at the 5th insertions which is at the left of x+5.
Also notice the 6th insertion would happens at left of x+6.
Here x+6 > x+5, notice the x+5 which is the start of spanNames at the stale version.
stop moving to x+6. It indicate the toCurrent mapping stack is being upside down.