[editor] Fix quotes in TextEditor

Correct german form: 99-66

projects/editor/src/app/text-editor/rich-text-editor.component.html

@@ -197,7 +197,7 @@
               [matTooltip]="'Geschütztes Leerzeichen'">&blank;</button>
       <button mat-button (click)="insertSpecialChar('&rsquo;')">&rsquo;</button>
       <button mat-button (click)="insertSpecialChar('&bdquo;')">&bdquo;</button>
-      <button mat-button (click)="insertSpecialChar('&rdquo;')">&rdquo;</button>
+      <button mat-button (click)="insertSpecialChar('&ldquo;')">&ldquo;</button>
       <button mat-button (click)="insertSpecialChar('&female;')">&female;</button>
       <button mat-button (click)="insertSpecialChar('&male;')">&male;</button>
       <button mat-button (click)="insertSpecialChar('&micro;')">&micro;</button>