Minor corrections to the formatting of manual page.

Minor corrections to the formatting of manual page.

Found with mandoc -Tlint; fixing the following messages:

WARNING: bad NAME section content
WARNING: missing comma before name
WARNING: new sentence, new line
WARNING: parenthesis in function name
WARNING: skipping no-space macro
WARNING: skipping paragraph macro
WARNING: unusual Xr order
WARNING: unusual Xr punctuation
STYLE: no blank before trailing delimiter
STYLE: possible typo in section name
STYLE: trailing delimiter
STYLE: whitespace at end of input line

For the meaning of the messages, see:
https://man.openbsd.org/mandoc#DIAGNOSTICS