Build/Tools: Fix typo in phpcs.xml.dist.

See #44366.

git-svn-id: https://develop.svn.wordpress.org/trunk@44507 602fd350-edb4-49c9-b593-d223f7449a82

Author: ocean90

phpcs.xml.dist

@@ -16,7 +16,7 @@
 	<!-- Strip the filepaths down to the relevant bit. -->
 	<arg name="basepath" value="./"/>
 
-	<!-- Check up to 20 files simultanously. -->
+	<!-- Check up to 20 files simultaneously. -->
 	<arg name="parallel" value="20"/>
 
 	<!-- Show sniff codes in all reports -->