Correcting typos and inconsistent capitalizations in French translation (2nd pass) by Ailothaen · Pull Request #3639 · sqlitebrowser/sqlitebrowser

Following this pull request 2 days ago: #3638

It is me again :)
When going through the menus in the latest nighly version, I noticed that some typos and inaccuracies were still present. So I went again though the translation file to correct them. Some descriptions were also made more clear (such as the one for printing, or the one for the REGEXP algorithm).
This should be the last PR on this!