LibJS: Use new format functions everywhere

This changes the remaining uses of the following functions across LibJS:

- String::format() => String::formatted()
- dbg() => dbgln()
- printf() => out(), outln()
- fprintf() => warnln()

I also removed the relevant 'LogStream& operator<<' overloads as they're
not needed anymore.

Libraries/LibJS/Parser.cpp

@@ -93,7 +93,7 @@ public:
     {
         int p = m_token_precedence[static_cast<size_t>(token)];
         if (p == 0) {
-            fprintf(stderr, "Internal Error: No precedence for operator %s\n", Token::name(token));
+            warnln("Internal Error: No precedence for operator {}", Token::name(token));
             ASSERT_NOT_REACHED();
             return -1;
         }