Fixed the wordings in r86296(py3k), r86297(release31-maint) and r86298(release27-maint).

David, for the examples you mentioned, the first one's parsing logic follows the explanation that is written. It is correct.

For the second example, the port value not being a DIGIT exhibits such a behavior.  I am unable to recollect the reason for this behavior. 
Either the URL is invalid (PORT is not a DIGIT, and parse module is simply ignoring to raise an error - it's okay, given the input is invalid) or it needs to distinguish the ':' as a port separator from path separator for some valid urls.

I think, if we find a better reason to change something for the second scenario, we shall address that.