After reviewing SRFI 14
(https://srfi.schemers.org/srfi-14/srfi-14.html#StandardCharsets)
there's more confusing terminology:

char-set:punctuation 	!"#%&'()*,-./:;?@[\]_{}
char-set:symbol 	$+<=>^`|~

Apparently ASCII makes a distinction between "punctuation" and "symbol"
characters. A table on Wikipedia confirms that:
<https://en.wikipedia.org/wiki/ASCII#Character_set>.

The distinction seems arbitrary. It's likely to cause confusion and be
of little use to Scheme programmers. Does Unicode make such a
distinction and does merging both of the above character classes into
one "punctuation" class make sense?

If we put ascii-symbol? into SRFI 174, people would probably think it
means the set of characters allowed in Scheme symbols.