edit / show title prop: add 'false' and callback choices

cypress/e2e/edit.cy.js

@@ -319,7 +319,7 @@ describe('Edit Page', () => {
         cy.get('body').click('left'); // dismiss notification
 
         cy.get('div[role="alert"]').should(el =>
-            expect(el).to.have.text('this title cannot be used')
+            expect(el).to.have.text('The form is invalid')
         );
 
         cy.get(ListPagePosts.elements.recordRows)

docs/Admin.md

@@ -209,7 +209,7 @@ const App = () => (
 
 ## `dashboard`
 
-By default, the homepage of an admin app is the `list` of the first child `<Resource>`. But you can also specify a custom component instead. To fit in the general design, use MUI's `<Card>` component, and react-admin's `<Title>` component to set the title in the AppBar:
+By default, the homepage of an admin app is the `list` of the first child `<Resource>`. But you can also specify a custom component instead. To fit in the general design, use MUI's `<Card>` component, and [react-admin's `<Title>` component](./Title.md) to set the title in the AppBar:
 
 ```jsx
 // in src/Dashboard.js
@@ -270,7 +270,7 @@ When users type URLs that don't match any of the children `<Resource>` component
 
 ![Not Found](./img/not-found.png)
 
-You can customize this page to use the component of your choice by passing it as the `catchAll` prop. To fit in the general design, use MUI's `<Card>` component, and react-admin's `<Title>` component:
+You can customize this page to use the component of your choice by passing it as the `catchAll` prop. To fit in the general design, use MUI's `<Card>` component, and [react-admin's `<Title>` component](./Title.md):
 
 ```jsx
 // in src/NotFound.js