when used with `--natbib` or `--biblatex`. These will treat a
bare number as a page locator, and they will be able to localize
it.
We borrow the code for stripping the locator label from the suffix
from Citeproc code. Note that the recognition of the locator label
is locale-sensitive; if `lang` is `de`, then `S. 33` is a page
reference, and `p. 33` is not!
Closes#9275.
