It's useful context for translators but it generates very spammy diffs whenever
a line is added or removed, changing the comments for hundreds or thousands of
msgids needlessly.
We still have the file names so it's relatively easy to search in file to find
the location of the source string.
Change extract script `path` argument to support specifying multiple
paths, like `makerst.py`. This prevents parsing invalid XML files while
scanning the whole repository.
(cherry picked from commit 87d23bf85a)