The code for handling multi-line types for arguments in "Args" sections

could lose spaces when breaking after a comma (for defining things like

"optional" or "unused" after a type). This happened because we stripped

each line before joining.
This change improves the processing, stripping only when part of an

argument reference (anything with a leading or trailing .).

Tested with single-line argument definitions and multiline (with . on

the previous line, next line, both, and with , optional and other text.