Momjian "Support Functions" section: possible typo and question

I am reading the Momjian "Support Functions" section and have the 
following comments:

1 - there is a comma after "BOTH" that is not before "LEADING" or 
"TRAILING", so I believe it is an error.

     trim(BOTH...)    trim(BOTH, col)    same as trim()
     trim(LEADING...)    trim(LEADING col)    col with leading spaces 
removed
     trim(TRAILING...)    trim(TRAILING col)    col with trailing 
spaces removed

2 - I typed \h trim and no help came up. Is it required to resort 
to HTML documentation for docs on this function