State more clearly that substr-eq matches substring exactly

lib/Type/Str.pod

@@ -457,7 +457,7 @@ Examples:
     multi method substr-eq(Str:D:  Str(Cool) $test-string, Int(Cool) $from) returns Bool
     multi method substr-eq(Cool:D: Str(Cool) $test-string, Int(Cool) $from) returns Bool
 
-Returns C<True> if the C<$test-string> matches the C<String> object,
+Returns C<True> if the C<$test-string> exactly matches the C<String> object,
 starting from the given initial index C<$from>.  For example, beginning with
 the string C<"foobar">, the substring C<"bar"> will match from index 3: