Fixes an issue where symbol->string was failing
Fixes an issue where symbol->string was failing

In some instances apropos-information-list returns a string and not a
list of symbols; this is the case for Chicken's builtins, like C_plus.

IE, the following would fail:
(geiser-autodoc #f '(+))

This fixes jaor/geiser#72

ChaosEternal/geiser