Problem:
str_byteindex_enc could return an error if the index was longer than the
lline length. This was handled in each of the calls to it individually
Solution:
* Fix the call at the source level so that if the index is higher than
the line length, line length is returned as per LSP specification
* Remove pcalls on str_byteindex_enc calls. No longer needed now that
str_byteindex_enc has a bounds check.