Update asciidoc processing from locale module.
- Previously, a plain/text mime verification was applied against
incoming files. This worked well for articles and manpages documents
written in asciidoc format but it failed for manpage documents
written in asciidoc format which first line is prepare(1). In this
last case, even the incoming file is visibly a plain/text file, the
command file interprets it as an image/x-3ds file which made
plain/text mime verification to fail. This update changes the
verification from mime to match, using the incoming file extension
as reference, in order for manpage documents with prepare(1) as
first line to succeed localization update.