Updated some layouts for misconceptions between 'apostrophe' and 'grave' & updated description for modi (kagapa).

Some layouts, especially kagapa phonetic layouts have a misconception between grave accent and apostrophe. Therefore, they have mapped apostrophe in the place of grave accent. This is causing two apostrophes and no grave accent. Therefore they are updated and grave accent is added.

Also, updated description for modi(kagapa) layout.