Add RN support

[Willem3141]

• [x] Support the ù
  • [x] when searching for u or ù, show results for both (for now, may eventually depend on the dialect mode)
• [ ] Make a settings toggle for the dialect mode: enable or disable showing ù
  • [ ] potentially: show this menu at first load?
  • [ ] otherwise: decide on the default
  • [ ] if showing ù is disabled, then replace all ù by u (and potentially don't show IPA for RN)
• [x] Update IPA generation
  • [x] sy becomes sh
  • [x] ejectives become voiced stops at the beginning of a syllable
  • [x] remove glottal stops between vowels (and remove it optionally between equal vowels)
  • [x] add support for ù
  • [x] for FN, properly show both variants for closed syllables with u or ù

[Willem3141]

I think the current implementation of RN is enough for now. We aren't showing ù yet, but since we don't have a list of words that has ù any such implementation would show incomplete data. The IPA does have support for words that have ù.

[Willem3141]

And now we do have the list!