Update toShahmukhi with appropriate end of character transliteration

[Harjot1Singh]

https://github.com/shabados/gurmukhi-utils/blob/f0a2bfae4a927306f5a9670ea3d39eb06f8c13e5/lib/toShahmukhi.js#L108

This would also need to be updated.

Perhaps best to open a new issue for you to work on, I don't know how to fix the tests on this

Please allow this PR to be merged in for the time being

Originally posted by @bhajneet in https://github.com/shabados/gurmukhi-utils/pull/177#issuecomment-720873846