Issue #25523: Correct "a" article to "an" article
This changes the main documentation, doc strings, source code comments, and a
couple error messages in the test suite. In some cases the word was removed
to fix the grammar.
diff --git a/Misc/cheatsheet b/Misc/cheatsheet
index 3e603fc..0867079 100644
--- a/Misc/cheatsheet
+++ b/Misc/cheatsheet
@@ -953,7 +953,7 @@
instanceobject as arg, returns list of names in its attr.
dict.
divmod(a,b) Returns tuple of (a/b, a%b)
-enumerate(seq) Return a iterator giving: (0, seq[0]), (1, seq[1]), ...
+enumerate(seq) Return an iterator giving: (0, seq[0]), (1, seq[1]), ...
eval(s[, globals[, Eval string s in (optional) globals, locals contexts.s must
locals]]) have no NUL's or newlines. s can also be acode object.
Example: x = 1; incr_x = eval('x + 1')