Merge pull request #35536 from bfredl/skipahead

perf(highlight): allow decoration providers to skip ranges without data

fixes #35644

runtime/doc/api.txt

@@ -3362,6 +3362,12 @@ nvim_set_decoration_provider({ns_id}, {opts})
                    included. >
                     ["range", winid, bufnr, begin_row, begin_col, end_row, end_col]
 <
+                   In addition to returning a boolean, it is also allowed to
+                   return a `skip_row, skip_col` pair of integers. This
+                   implies that this function does not need to be called until
+                   a range which continues beyond the skipped position. A
+                   single integer return value `skip_row` is short for
+                   `skip_row, 0`
                  • on_end: called at the end of a redraw cycle >
                     ["end", tick]
 <