fix typo, add dot at the end

Author: kaznovac

performance.rst

@@ -128,10 +128,10 @@ deployment process too):
     $ composer dump-autoload --no-dev --classmap-authoritative
 
 * ``--no-dev`` excludes the classes that are only needed in the development
-  environment (i.e. ``require-dev`` dependancies and ``autoload-dev`` rules);
+  environment (i.e. ``require-dev`` dependencies and ``autoload-dev`` rules);
 * ``--classmap-authoritative`` creates a class map for PSR-0 and PSR-4 compatible classes
   used in your application and prevents Composer from scanning the file system for
-  classes that are not found in the class map. (see: `Composer's autoloader optimization`_)
+  classes that are not found in the class map. (see: `Composer's autoloader optimization`_).
 
 Learn more
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