join(1) documentation

[Dan Jacobson]

Regarding Info page 8.3 `join': Join lines on a common field
   However, as a GNU extension, if the input has no unpairable lines the
   sort order can be any order that considers two fields to be equal if and
   only if the sort comparison described above considers them to be equal.
   For example:
Say if this is a GNU extension example or a regular example or both.
Best to give one regular example before mentioning extensions.
       $ cat file1
       a a1
       c c1
Say what should happen if we have this additional line here:
       c c3
Indeed, the user might be wanting to do "join file1 file1" with such
lines! Say if join is useful or will just silently ignore them, and he
should import into a SQL machine instead.

     * fields in the input are separated by one or more blanks, with
       leading       blanks on the line ignored;
Why the        ^^^^^ mysterious blanks inserted above?

     * fields in the output are separated by a space;
Space, blanks, use consistent wording. P.S., Man page says whitespace. Info
page does not.