questions regading some encoding troubles in webwml

Hi,

After observing the following broken char here:
Introduction � l'empaquetage Debian
<https://www.debian.org/doc/devel-manuals#packaging-tutorial> in
https://www.debian.org/doc/index.fr.html

For that I went to its source file in the salsa module. But:
1. the rendering in salsa is surprising because it seems to handle a
mixed-encoding situation, and so here we cannot see the mismatch:
https://salsa.debian.org/webmaster-team/webwml/-/blob/master/french/doc/index.wml
2. I also observed some encoding variations regarding the apostrophe
character that sometimes is the classic (U+0027) or the (U+2019). In my
opinion, an apostrophe should be U+0027 and U+2019 uses for the right close
single quotation mark.

So have Debian any rules/recommendations on the formal content?
Any tool used to validate before (or after) any changes? (like a testcheck
in its make?)
Otherwise may I proceed directly using the edition facility of salsa?

Thanks,
Patrice