Fix a few grammatical issues to comply with existing rules :
- space before "!" in fr str for "error_compose_character_limit" as in fr str for "footer_empty"
- second part of negation added in fr str for "error_media_upload_opening", "error_media_upload_sending", "error_failed_app_registration" (ne ... pas) as in fr str for "error_empty" and others
- added a period in fr str for "dialog_whats_an_instance"
Some typos have been fixed and terminology changes have been suggested.
Also the gender-inclusive marks have been removed: independently
of our personal opinions regarding which sociological features
a written language should or shouldn’t take into account,
the fact remains that interpunct, hyphen, slash and apostrophe
are not admitted characters to highlight the feminine gender
due to the reading issues that would come out of those
graphical modifications. Moreover, those marks do not take into account
accessibility problems either (screen readers, etc.).
Therefore French grammatical rules should logically prevail.
