Better comment for why U+F020 isn't used, as suggested in #268

css/font-awesome.css

@@ -107,7 +107,7 @@ li[class^="icon-"].icon-large:before, li[class*=" icon-"].icon-large:before {
 .icon-play-circle:before          { content: "\f01d"; }
 .icon-repeat:before               { content: "\f01e"; }
 
-/* \f020 is not a valid unicode character. all shifted one down */
+/* \f020 doesn't work in Safari. all shifted one down */
 .icon-refresh:before              { content: "\f021"; }
 .icon-list-alt:before             { content: "\f022"; }
 .icon-lock:before                 { content: "\f023"; }

docs/assets/css/font-awesome.css

@@ -107,7 +107,7 @@ li[class^="icon-"].icon-large:before, li[class*=" icon-"].icon-large:before {
 .icon-play-circle:before          { content: "\f01d"; }
 .icon-repeat:before               { content: "\f01e"; }
 
-/* \f020 is not a valid unicode character. all shifted one down */
+/* \f020 doesn't work in Safari. all shifted one down */
 .icon-refresh:before              { content: "\f021"; }
 .icon-list-alt:before             { content: "\f022"; }
 .icon-lock:before                 { content: "\f023"; }

docs/assets/less/font-awesome.less

@@ -131,7 +131,7 @@ ul.icons {
 .icon-play-circle:before          { content: "\f01d"; }
 .icon-repeat:before               { content: "\f01e"; }
 
-/* \f020 is not a valid unicode character. all shifted one down */
+/* \f020 doesn't work in Safari. all shifted one down */
 .icon-refresh:before              { content: "\f021"; }
 .icon-list-alt:before             { content: "\f022"; }
 .icon-lock:before                 { content: "\f023"; }

less/font-awesome.less

@@ -133,7 +133,7 @@ ul.icons {
 .icon-play-circle:before          { content: "\f01d"; }
 .icon-repeat:before               { content: "\f01e"; }
 
-/* \f020 is not a valid unicode character. all shifted one down */
+/* \f020 doesn't work in Safari. all shifted one down */
 .icon-refresh:before              { content: "\f021"; }
 .icon-list-alt:before             { content: "\f022"; }
 .icon-lock:before                 { content: "\f023"; }

sass/font-awesome.sass

@@ -170,7 +170,7 @@ ul.icons
 .icon-repeat:before
   content: "\f01e"
 
-/* \f020 is not a valid unicode character. all shifted one down
+/* \f020 doesn't work in Safari. all shifted one down
 .icon-refresh:before
   content: "\f021"
 

sass/font-awesome.scss

@@ -133,7 +133,7 @@ ul.icons {
 .icon-play-circle:before          { content: "\f01d"; }
 .icon-repeat:before               { content: "\f01e"; }
 
-/* \f020 is not a valid unicode character. all shifted one down */
+/* \f020 doesn't work in Safari. all shifted one down */
 .icon-refresh:before              { content: "\f021"; }
 .icon-list-alt:before             { content: "\f022"; }
 .icon-lock:before                 { content: "\f023"; }