Changed back to original icon of Edit Description.

Thanks to saschafoerster, C0rn3j and xet7 !

Fixes #5413,
related https://github.com/wekan/wekan/commit/1f2fb2ccce38e9cac348f1c459784d6e5a949ded

client/components/cards/cardDetails.jade

@@ -526,7 +526,7 @@ template(name="cardDetails")
             else
               if currentBoard.allowsDescriptionText
                 a.js-open-inlined-form(title="{{_ 'edit'}}" value=title)
-                  i.fa.fa-plus
+                  i.fa.fa-pencil-square-o
                 if getDescription
                   +viewer
                     = getDescription