doc/fields: add section for nillable-required fields

doc/website/src/css/custom.css

@@ -868,4 +868,26 @@ div[class^='announcementBar_'] {
           var(--site-announcement-bar-stripe-color2) 40px
   );
   font-weight: bold;
+}
+
+.code-block-error-message {
+  background-color: #ff6f8780;
+  display: block;
+  margin: 0 calc(-1 * var(--ifm-pre-padding));
+  padding: 0 var(--ifm-pre-padding);
+  border-left: 3px solid #ff6f87a0;
+}
+.code-block-error-message span {
+  color: rgb(191, 199, 213)!important;
+}
+
+.code-block-info-line {
+  background-color: rgb(193 230 140 / 25%);
+  display: block;
+  margin: 0 calc(-1 * var(--ifm-pre-padding));
+  padding: 0 var(--ifm-pre-padding);
+  border-left: 3px solid rgb(193 230 140 / 80%);
+}
+.code-block-info-line span.token.comment {
+  color: #c4c4c4!important;
 }

doc/website/src/pages/index.js

@@ -9,9 +9,8 @@
  */
 
 const React = require('react');
-import LayoutProviders from '@theme/LayoutProviders';
+import LayoutProvider from '@theme/Layout/Provider';
 import Footer from '@theme/Footer';
-import Navbar from '@theme/Navbar';
 import Link from '@docusaurus/Link';
 
 
@@ -191,12 +190,12 @@ class Index extends React.Component {
 }
 
 export default function (props) {
-    return <LayoutProviders>
+    return <LayoutProvider>
         {/*<div className={"section_index"}>*/}
         {/*    <Navbar/>*/}
         {/*</div>*/}
         <HomeNav />
         <Index {...props} />
         <Footer/>
-    </LayoutProviders>;
+    </LayoutProvider>;
 };