assoc-string-equal requires that x is a string
and alist is an alist.
Major Section: PROGRAMMING
(Assoc-string-equal x alist) is similar to assoc-equal.
However, for string x and alist alist, the comparison of x
with successive keys in alist is done using string-equal
rather than equal.
The guard for assoc-string-equal requires that x is a string
and alist is an alist.