add prettier for auto formatting (#231)

* [Prettier] Add "prettier"

Makes the formatting of the code consistent.
By using the eslint-plugin-prettier formatting issues will be highlighted as a lint error.
These errors will be auto fixed by running "lint --fix" (which can be done automatically on file save)

* [Prettier] Add "prettier" - Fix formatting

src/components/reader/PageNumber.tsx

@@ -9,27 +9,28 @@ import React from 'react';
 import { Box } from '@mui/system';
 
 interface IProps {
-    settings: IReaderSettings
-    curPage: number
-    pageCount: number
+    settings: IReaderSettings;
+    curPage: number;
+    pageCount: number;
 }
 
 export default function PageNumber(props: IProps) {
     const { settings, curPage, pageCount } = props;
 
     return (
-        <Box sx={{
-            display: settings.showPageNumber ? 'block' : 'none',
-            position: 'fixed',
-            bottom: '50px',
-            right: settings.staticNav ? 'calc((100vw - 325px)/2)' : 'calc((100vw - 25px)/2)',
-            padding: '2px',
-            paddingLeft: '4px',
-            paddingRight: '4px',
-            textAlign: 'center',
-            backgroundColor: 'rgba(0, 0, 0, 0.3)',
-            borderRadius: '10px',
-        }}
+        <Box
+            sx={{
+                display: settings.showPageNumber ? 'block' : 'none',
+                position: 'fixed',
+                bottom: '50px',
+                right: settings.staticNav ? 'calc((100vw - 325px)/2)' : 'calc((100vw - 25px)/2)',
+                padding: '2px',
+                paddingLeft: '4px',
+                paddingRight: '4px',
+                textAlign: 'center',
+                backgroundColor: 'rgba(0, 0, 0, 0.3)',
+                borderRadius: '10px',
+            }}
         >
             {`${curPage + 1} / ${pageCount}`}
         </Box>