When checking for forbidden code points, we should process constant values (duh). (#321)

Author: lemire

include/ada/unicode.h

@@ -86,7 +86,7 @@ ada_really_inline constexpr bool is_forbidden_host_code_point(
  * @see https://url.spec.whatwg.org/#forbidden-domain-code-point
  */
 ada_really_inline constexpr bool contains_forbidden_domain_code_point(
-    char* input, size_t length) noexcept;
+    const char* input, size_t length) noexcept;
 
 /**
  * Checks if the input is a forbidden doamin code point.

src/unicode.cpp

@@ -131,7 +131,7 @@ ada_really_inline constexpr bool is_forbidden_domain_code_point(
 }
 
 ada_really_inline constexpr bool contains_forbidden_domain_code_point(
-    char* input, size_t length) noexcept {
+    const char* input, size_t length) noexcept {
   size_t i = 0;
   uint8_t accumulator{};
   for (; i + 4 <= length; i += 4) {