feat: add padlock next to private collections in lists

shared/components/Breadcrumb.js

@@ -7,6 +7,7 @@ import { Link } from 'react-router-dom';
 import {
   CollectionIcon,
   PrivateCollectionIcon,
+  PadlockIcon,
   GoToIcon,
   MoreIcon,
 } from 'outline-icons';
@@ -32,6 +33,11 @@ const Breadcrumb = observer(({ document, collections, onlyText }: Props) => {
   if (onlyText === true) {
     return (
       <React.Fragment>
+        {collection.private && (
+          <React.Fragment>
+            <SmallPadlockIcon color="currentColor" size={16} />{' '}
+          </React.Fragment>
+        )}
         {collection.name}
         {path.map(n => (
           <React.Fragment key={n.id}>
@@ -83,6 +89,11 @@ const Wrapper = styled(Flex)`
   `};
 `;
 
+const SmallPadlockIcon = styled(PadlockIcon)`
+  display: inline-block;
+  vertical-align: sub;
+`;
+
 const SmallSlash = styled(GoToIcon)`
   width: 15px;
   height: 10px;