DOC: public fn alignment::sparse::expand_kmer_matches not documented

[corneliusroemer]

The following public function lacks a doc string:

rust-bio/src/alignment/sparse.rs

Line 398 in 43d198e

pub fn expand_kmer_matches(

Some important questions to answer:

• exact meaning of allowed_mismatches, if I read the code correctly, extension happens independently on either side of the k-mer match, and stops after allowed_mismatches in each direction. So if you specify allowed_mismatches = 1 the extended match will actually contain 2 mismatches, one on either side - which is not what one may expect at all.
• whether output matches can overlap or not, if they don't overlap, will adjoining matches be merged or just border directly side-by-side?