Add 's' method to access theme props (#5163)

shared/editor/components/FileExtension.tsx

@@ -1,6 +1,7 @@
 import { AttachmentIcon } from "outline-icons";
 import * as React from "react";
 import styled from "styled-components";
+import { s } from "../../styles";
 import { stringToColor } from "../../utils/color";
 
 type Props = {
@@ -27,7 +28,7 @@ export default function FileExtension(props: Props) {
 }
 
 const Icon = styled.span<{ $size: number }>`
-  font-family: ${(props) => props.theme.fontFamilyMono};
+  font-family: ${s("fontFamilyMono")};
   display: inline-flex;
   align-items: center;
   justify-content: center;