Fixed misspelling. There is only one 'c' in the word necessarily.

Author: cjus

doc/en/core/semicolon.md

@@ -84,7 +84,7 @@ Below is the result of the parser's "guessing" game.
     })(window); //<- inserted
 
 > **Note:** The JavaScript parser does not "correctly" handle return statements 
-> that are followed by a new line. While this is not neccessarily the fault of 
+> that are followed by a new line. While this is not necessarily the fault of
 > the automatic semicolon insertion, it can still be an unwanted side-effect. 
 
 The parser drastically changed the behavior of the code above. In certain cases,