Minimum PR size

[Jason Schroeder via Digitalmars-d-learn]

I am interested in contributing to D on GitHub, and was wondering 
if there is a minimum or preferabe minimum size of a pull 
request; e.g. I woukd like to work on increasing code coverage, 
and am wondering if a pull request with one additional line of 
code, e.g. one assert () in a unittest block, would be considered 
not worth the time to consider as a PR?