Properly unstyle the .list-unstyled class by switching from margin to padding

Also add better comments

docs/assets/css/bootstrap.css

@@ -516,12 +516,12 @@ ol ul {
 }
 
 .list-unstyled {
-  margin-left: 0;
+  padding-left: 0;
   list-style: none;
 }
 
 .list-inline {
-  margin-left: 0;
+  padding-left: 0;
   list-style: none;
 }
 

less/type.less

@@ -118,9 +118,9 @@ ol ul {
 
 // List options
 
-// Unstyled keeps list items block level, just removes list-style
+// Unstyled keeps list items block level, just removes default browser padding and list-style
 .list-unstyled {
-  margin-left: 0;
+  padding-left: 0;
   list-style: none;
 }
 // Inline turns list items into inline-block