Fix FontAwesome checkmark icon for the copy button inside code snippets as well as the plus icon in _yuga_content

Author: Andrew Cai

styles/_toc.scss

@@ -88,8 +88,9 @@ pre code.copy + textarea + button.copy, .copy pre code + textarea + button.copy,
     position: absolute;
     top: 0;
     left: 0;    
-    font: normal normal normal 18px/1 FontAwesome;
-    content: '\F00C';
+    font: normal normal normal 18px/1 'Font Awesome 5 Free';
+    font-weight: 900;
+    content: '\f00c';
     color: #fff;
     text-align: center;
     border-radius: 2px;

styles/_yuga_content.scss

@@ -43,7 +43,8 @@
         list-style-type: none;
         &:before {
           content: '\f067';
-          font-family: 'FontAwesome';
+          font-family: 'Font Awesome 5 Free';
+          font-weight: 900;
           font-size: 13px;
           background-color: transparent;
           border: none;