chore: Fix grammar

Signed-off-by: txtsd <code@ihavea.quest>

config.js

@@ -302,7 +302,7 @@ Number.prototype.div = function (divisor) {
 
 
 function LevelUpTime(level) {  // seconds
-  // 20 minutes for for level 1
+  // 20 minutes for level 1
   // exponential increase after that
   return Math.round((20 + Math.pow(1.15, level)) * 60);
 }

json2.js

@@ -210,7 +210,7 @@ if (!this.JSON) {
 
 // If the string contains no control characters, no quote characters, and no
 // backslash characters, then we can safely slap some quotes around it.
-// Otherwise we must also replace the offending characters with safe escape
+// Otherwise, we must also replace the offending characters with safe escape
 // sequences.
 
         escapable.lastIndex = 0;