This should prevent occurrences of the search string from being found in other
locations (e.g. in a comment).
The whole approach of string extraction from Rust sources is sketchy,
but this at least prevents producing garbage when the content of a string
appears somewhere else unquoted.
The previous version generates files which do not preserve the line number from
the original fish script file, resulting in translation not working.
The new approach is quite ugly, and might have some issues,
but at least it seems to work in some cases.
Extracting explicit and implicit messages works essentially the same way, which
is also reflected in the code being identical, except for the regex.
Extract the duplicated code into a function.
This is absolutely disgusting code, but it works out okay-ish.
The problem is xgettext has no rust support (it's stuck in review
limbo). So we use cargo-expand to extract all invocations of
gettext, and massage all that to generate a
messages.pot ourselves.
We also assume any string constant could be translated.
Instead of using /tmp/fish as a temporary directory for this operation,
which could lead to clobbering user files, use mktemp to create an
actual temporary directory.
This change does several things. First, it works around a quirk of the
`xgetttext` command that only recognizes description strings in even
numbered position on the command. Second, it allows descriptions
introduced by the `-d` short flag to be recognized.
More importantly, it normalizes the strings so that `xgettext` correctly
extracts them into the *.po file. Prior to this change many fish script
strings were ignored due to how they were written (e.g., single versus
double quotes).
Fixes#4073
