Computes a `PangoLogAttr` for each character in
attrs array must have one `PangoLogAttr` for each position in
text contains N characters,
it has N+1 positions, including the last position at the end of the text.
text should be an entire paragraph; logical attributes
can't be computed without context (for example you need to see spaces on either side of a word to know the word is a word).
text to process. Must be valid UTF-8
length in bytes of
embedding level, or -1 if unknown
array with one `PangoLogAttr` per character in