trivial code comments

src/duk_builtin_string.c

@@ -212,6 +212,9 @@ int duk_builtin_string_prototype_substring(duk_context *ctx) {
 	/* FIXME: this coercion works incorrectly for number values outside
 	 * integer range; e.g. Number.POSITIVE_INFINITY as an endpoint must
 	 * clamp to 'len'.
+	 *
+	 * FIXME: add a helper for getting a clamped ToInteger() coercion,
+	 * it is also needed for e.g. radix handling.
 	 */
 
 	start_pos = duk_to_int(ctx, 0);

src/extract_caseconv.py

@@ -7,9 +7,15 @@
 #
 #  There is no support for context or locale sensitive rules, as they
 #  are handled directly in C code before consulting tables generated
-#  here.  Case conversion rules for ASCII are also excluded as they are
+#  here.  Ecmascript requires case conversion both with and without
+#  locale/language specific rules (e.g. String.prototype.toLowerCase()
+#  and String.prototype.toLocaleLowerCase()), so they are best handled
+#  in C anyway.
+#
+#  Case conversion rules for ASCII are also excluded as they are
 #  handled by C fast path.  Rules for non-BMP characters (codepoints
-#  above U+FFFF) are omitted as they're not required for standard Ecmascript.
+#  above U+FFFF) are omitted as they're not required for standard
+#  Ecmascript.
 #
 
 import os, sys, math