[remark-typo]: french quotes not inserted on some WTF cases

[artragis]

Here is the sentence :

Les propriétaires de l'application créent un <<contenu>>, lui donne des <<méta données>> et les visiteurs vont pouvoir accéder à la fiche ainsi rédigée de ces contenus.

Here is the result :

Un CMS distingue deux types d’utilisateurs : les propriétaires et les visiteurs. Le concept est le suivant : Les propriétaires de l’application créent un <<contenu>>, lui donne des «méta données» et les visiteurs vont pouvoir accéder à la fiche ainsi rédigée de ces contenus.

the "contenu" part is not properly translated. It is translated if we put a blanck space between << and c.

It is expected not to have to put this extra space.

[artragis]

Another one is when the << >> elements are inside a list element.

[AmauryCarrade]

Also for the <<méta données>> part (i.e. when characters are correctly replaced), inner non-breaking spaces (U+00A0) are not inserted; I think they should be, so to respect French typography.

[StaloneLab]

I recently investigated this problem, which was more complicated than I expected, and am left with the following:

• allowing the syntax without space would be complicated, because of how remark works internally, and of how the plugin was designed (visiting the tree after tokenization). I am not ready to rewrite this plugin (or any other) without a micromark migration (because the job would be done twice), but anyway I take note of this issue;
• what I suggest is therefore to enforce the following syntax: << [content] >>, with spaces inside, that will be replaced by NBSP. It would solve the issue in the following way: <<méta données>> will give the same result as <<contenu>>: no french quotes.

[artragis]

good to me. The issue was coming from inconsistancy, so it would solve it.

[StaloneLab]

Okay, finally we should be able to solve it correctly. I found one of our plugins, remark-fix-guillemets, which already does what we want. It was certainly forgotten during one of the refactorings. I included it in my PR for ZMarkdown 11.2. The problem reported by @AmauryCarrade about adding NBSP was also solved by a simple fix to the plugin.