The Romanian Wikipedia has a script working for the classic editor, that transforms cedilla-below letters (ş, ţ) in comma-below (ș, ț) when the page is saved. 
We need a similar script working for visual editor. My initial idea was to add a hook in the VE before the page is saved (see T59536), but this was declined by the VE team, so we'll need an alternative solution.
The solution needs to take into account the fact that there are legitimate reasons why a user will want to include text using the old diacritics, especially regarding s-cedilla.
I'm willing to work on this issue myself if a solution that is acceptable for all involved parties is found.