Problem:
`get_node_text()` returned inconsistent results between buffer and
string sources when a node's range ends at `end_col == 0` (i.e. the node
ends with a newline). The buffer path dropped the trailing newline; the
string path included it correctly.
Solution:
Append `'\n'` in `buf_range_get_text()` when `end_col == 0` and
`start_row ~= end_row`. The `start_row ~= end_row` guard excludes
zero-width nodes at column 0, which should return `""`.
Remove the workaround in the `#trim!` directive that manually
compensated for the missing newline.
Strip whitespace in `resolve_lang()` so injection language nodes ending
at `end_col == 0` (e.g. `">lua\n"`) still resolve correctly.
7ed5609439
