Enable CodeClimate SCSS Lint checks (#2886)

* add scss_lint to Gemfile

* add .scss-lint.yml

* fix warnings of scss-lint

* chmod -x styles/variables.scss

* Enable CodeClimate SCSS Lint checks

app/javascript/styles/about.scss

@@ -44,7 +44,8 @@
     color: $color2;
   }
 
-  ul, ol {
+  ul,
+  ol {
     list-style: inherit;
     margin-left: 20px;
 
@@ -57,11 +58,13 @@
     }
   }
 
-  li > ol, li > ul {
+  li > ol,
+  li > ul {
     margin-top: 20px;
   }
 
-  p, li {
+  p,
+  li {
     font: 16px/28px 'mastodon-font-sans-serif', sans-serif;
     font-weight: 400;
     margin-bottom: 12px;
@@ -74,7 +77,7 @@
 
   em {
     display: inline-block;
-    padding: 7px 7px 5px 7px;
+    padding: 7px 7px 5px;
     margin: 0 2px;
     background: $color3;
     color: $color1;
@@ -134,7 +137,8 @@
     text-align: right;
     font: 16px/28px 'mastodon-font-sans-serif', sans-serif;
 
-    span, strong {
+    span,
+    strong {
       display: block;
     }
 
@@ -333,7 +337,8 @@
     }
   }
 
-  .simple_form, .closed-registrations-message {
+  .simple_form,
+  .closed-registrations-message {
     width: 300px;
     flex: 0 0 auto;
     background: rgba(darken($color1, 7%), 0.5);
@@ -359,7 +364,8 @@
       display: none;
     }
 
-    .simple_form, .closed-registrations-message {
+    .simple_form,
+    .closed-registrations-message {
       flex: auto;
     }
   }