Misspelling check.

Fixed the spelling using the following command:

  misspellings -s fix.sh $(find * -type f)
  sh fix.sh

Nothing very important, just was using it for a quick test.

libs/bottle.py

@@ -1457,7 +1457,7 @@ class JSONPlugin(object):
             if isinstance(rv, dict):
                 #Attempt to serialize, raises exception on failure
                 json_response = dumps(rv)
-                #Set content type only if serialization succesful
+                #Set content type only if serialization successful
                 response.content_type = 'application/json'
                 return json_response
             return rv