[iip] Inconsistent deletion behaviour (#97)

r12a has just created a new issue for https://github.com/w3c/iip:

== Inconsistent deletion behaviour ==
This behavior varies even between different applications within macOS. Apple Pages seems to delete / select / cursor by Vowel+Consonant cluster. TextEdit seems to delete by code point, but cursor / select is by Vowel + Consonant cluster. In general, the TextEdit behavior seems favorable.

Gurmukhi has only three commonly used half/subjoined consonants for ਹ ਵ and ਰ. Most Gurmukhi readers are not familiar with the concept of Halant / Virama and thus deleting behavior should delete the full half-character.

Please view or discuss this issue at https://github.com/w3c/iip/issues/97 using your GitHub account