feat: Backlinks (#979)

* feat: backlinks

* feat: add backlinkDocumentId to documents.list

* chore: refactor
fix: create and delete backlink handling

* fix: guard against self links

* feat: basic frontend
fix: race condition

* styling

* test: fix parse ids

* self review

* linting

* feat: Improved link styling

* fix: Increase clickable area at bottom of doc / between references

* perf: global styles are SLOW

app/scenes/Document/components/Editor.js

@@ -1,8 +1,6 @@
 // @flow
 import * as React from 'react';
-import styled from 'styled-components';
 import Editor from 'components/Editor';
-import Placeholder from 'rich-markdown-editor/lib/components/Placeholder';
 import ClickablePadding from 'components/ClickablePadding';
 import plugins from './plugins';
 
@@ -33,7 +31,7 @@ class DocumentEditor extends React.Component<Props> {
 
     return (
       <React.Fragment>
-        <StyledEditor
+        <Editor
           ref={ref => (this.editor = ref)}
           plugins={plugins}
           {...this.props}
@@ -47,23 +45,4 @@ class DocumentEditor extends React.Component<Props> {
   }
 }
 
-const StyledEditor = styled(Editor)`
-  justify-content: start;
-
-  > div {
-    transition: ${props => props.theme.backgroundTransition};
-  }
-
-  p {
-    ${Placeholder} {
-      visibility: hidden;
-    }
-  }
-  p:nth-child(2):last-child {
-    ${Placeholder} {
-      visibility: visible;
-    }
-  }
-`;
-
 export default DocumentEditor;