Update stress marker logic to better account for digraphs

[charlesLoder]

In the same context, when we have a q̟ with dagesh chazaq q̟q̟ and between them there is a primary stress, the COMBINING PLUS SIGN BELOW is moved under the primary stress as qˈ̟q̟. E.g. Gen. 2:8 מִקֶּ֑דֶם as miqˈ̟q̟ɛːðɛm

Originally posted by @johnlockejrr in #139

This is a similar issue to #141.

The stress marking logic does not handle digraphs.