Add some asserts in StringRegistry methods
Add some asserts in StringRegistry methods

lenormf/kakoune,lenormf/kakoune,flavius/kakoune,danielma/kakoune,danielma/kakoune,ekie/kakoune,flavius/kakoune,elegios/kakoune,Asenar/kakoune,rstacruz/kakoune,danr/kakoune,xificurC/kakoune,alexherbo2/kakoune,alpha123/kakoune,alexherbo2/kakoune,zakgreant/kakoune,ekie/kakoune,jjthrash/kakoune,Asenar/kakoune,zakgreant/kakoune,xificurC/kakoune,mawww/kakoune,danr/kakoune,jkonecny12/kakoune,Asenar/kakoune,jjthrash/kakoune,danr/kakoune,jkonecny12/kakoune,casimir/kakoune,Somasis/kakoune,elegios/kakoune,flavius/kakoune,xificurC/kakoune,casimir/kakoune,danr/kakoune,mawww/kakoune,mawww/kakoune,occivink/kakoune,mawww/kakoune,Somasis/kakoune,ekie/kakoune,casimir/kakoune,alexherbo2/kakoune,elegios/kakoune,rstacruz/kakoune,Somasis/kakoune,Asenar/kakoune,lenormf/kakoune,casimir/kakoune,rstacruz/kakoune,jjthrash/kakoune,jkonecny12/kakoune,occivink/kakoune,danielma/kakoune,zakgreant/kakoune,Somasis/kakoune,alpha123/kakoune,danielma/kakoune,jjthrash/kakoune,elegios/kakoune,jkonecny12/kakoune,alexherbo2/kakoune,occivink/kakoune,alpha123/kakoune,ekie/kakoune,occivink/kakoune,rstacruz/kakoune,lenormf/kakoune,zakgreant/kakoune,flavius/kakoune,alpha123/kakoune,xificurC/kakoune