Simplify possibly confusing code line

I may be wrong, but this line not only is wasteful
but seems a bit confusing: it may wrongly suggest
we will use the local `char` variable
with the next character one more time.

the-super-tiny-compiler.js

@@ -495,7 +495,7 @@ function tokenizer(input) {
       }
 
       // Skip the closing double quote.
-      char = input[++current];
+      ++current;
 
       // And add our `string` token to the `tokens` array.
       tokens.push({ type: 'string', value });