fix(lua): ensure inspect_pos() only shows visible highlight extmarks

Problem:  Unpaired marks are shown with `filter.extmarks == true`, which
          should only return visible highlights. Misleading `end_col`
          included in `inspect_pos()` for unpaired mark; it is set to
          `start_col + 1` which would be a visible highlight, which it is
          not. Custom "is_here" filter used to get extmarks overlapping a
          position.

Solution: Exclude unpaired highlight extmarks with `filter.extmarks == true`.
          Set `end_col` to `start_col` for an unpaired mark. Supply
          appropriate arguments to nvim_buf_get_extmarks() to return
          overlapping extmarks; exclude marks whose end is at `{row, col}`
          with `filter.extmarks == true`.

0 files changed, 0 insertions, 0 deletions