Update modules/ROOT/pages/creating-a-skin.adoc

Co-authored-by: Arvin(Jintao) Han <[email protected]>

Author: kemister85

modules/ROOT/pages/creating-a-skin.adoc

@@ -12,7 +12,7 @@ Before beginning, ensure that:
 
 * Familiarity with the command line and basic commands is established.
 * link:https://nodejs.org/en/[Node.js] and link:https://yarnpkg.com/en/[Yarn] are already installed.
-* A basic understanding of link:http://lesscss.org[Less], the CSS preprocessor used to build skins, is acquired. Specifically, review the link:http://lesscss.org/features/#variables-feature[section on variables].
+* A basic understanding of link:http://lesscss.org[Less], the CSS preprocessor used to build skins, is required. Specifically, review the link:http://lesscss.org/features/#variables-feature[section on variables].
 
 == Preparation