Re: [PATCH v4 27/38] i18n: config: unfold error messages marked for translation

> Introduced in 473166b ("config: add 'origin_type' to config_source
> struct", 2016-02-19), Git can inform the user about the origin of a
> config error, but the implementation does not allow translators to
> translate the keywords 'file', 'blob, 'standard input', and
> 'submodule-blob'. Moreover, for the second message, a reason for the
> error is appended to the message, not allowing translators to translate
> that reason either.
>
> Unfold the message into several templates for each known origin_type.
> That would result in better translation at the expense of code
> verbosity.
>
> Add enum git_config_oringin_type to ease management of the various
> configuration origin types (blob, file, etc).
>
> For the first instance, use xstrfmt() function to prepare the message
> string, instead of doing something like it's done for the second one,
> because intelligibility and code conciseness are improved for that
> instance.