getopt_long.3: wording quibbles

- Make wording more clear: "is expect" vs "is expected" [1]
- Remove extraneous trailing period..

Reported by:	dim [1]

lib/libc/stdlib/getopt_long.3

@@ -130,11 +130,11 @@ field should be one of:
 .Pp
 .Bl -tag -width ".Dv optional_argument" -offset indent -compact
 .It Dv no_argument
-no argument to the option is expect
+no argument to the option is expected
 .It Dv required_argument
 an argument to the option is required
 .It Dv optional_argument
-an argument to the option may be presented.
+an argument to the option may be presented
 .El
 .Pp
 If