Everywhere: Add sv suffix to strings relying on StringView(char const*)

Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).

No functional changes.

Userland/Libraries/LibWeb/Bindings/CSSNamespace.cpp

@@ -56,7 +56,7 @@ JS_DEFINE_NATIVE_FUNCTION(CSSNamespace::supports)
         }
         // Otherwise, if property is a custom property name string, return true.
         // FIXME: This check is not enough to make sure this is a valid custom property name, but it's close enough.
-        else if (property_name.starts_with("--") && property_name.length() >= 3) {
+        else if (property_name.starts_with("--"sv) && property_name.length() >= 3) {
             return JS::Value(true);
         }