Indicate valid and invalid fields in signup form (#1450)

* Use was-validated class in signup form

* Update signup.tsx

* Update signup.tsx

---------

Co-authored-by: SleeplessOne1917 <abias1122@gmail.com>

src/shared/components/home/signup.tsx

@@ -140,7 +140,10 @@ export class Signup extends Component<any, State> {
   registerForm() {
     const siteView = this.state.siteRes.site_view;
     return (
-      <form onSubmit={linkEvent(this, this.handleRegisterSubmit)}>
+      <form
+        className="was-validated"
+        onSubmit={linkEvent(this, this.handleRegisterSubmit)}
+      >
         <h5>{this.titleName(siteView)}</h5>
 
         {this.isLemmyMl && (