add_a
NAME
add_a() - prefix a string with the correct indefinite article
SYNOPSIS
string add_a( string str );
DESCRIPTION
Returns `str` with "a " or "an " prepended, choosing the article
from the following word's sound rather than just its first letter:
vowels take "an", but the special cases "us..." ("a user", "a use"),
"hour..." ("an hour"), and words already beginning "a "/"an " are
handled. A string of only spaces yields "a ".
SEE ALSO
add_a(3), vowel(3)