docs: fix broken example due to missing input module import (#27637)

Author: guiseek

src/components-examples/material/sidenav/BUILD.bazel

@@ -24,6 +24,7 @@ ng_module(
         "//src/material/select",
         "//src/material/sidenav",
         "//src/material/toolbar",
+        "//src/material/input",
         "@npm//@angular/forms",
         "@npm//@angular/platform-browser",
         "@npm//@angular/platform-browser-dynamic",

src/components-examples/material/sidenav/sidenav-fixed/sidenav-fixed-example.ts

@@ -5,6 +5,7 @@ import {MatFormFieldModule} from '@angular/material/form-field';
 import {MatCheckboxModule} from '@angular/material/checkbox';
 import {MatSidenavModule} from '@angular/material/sidenav';
 import {MatToolbarModule} from '@angular/material/toolbar';
+import {MatInputModule} from '@angular/material/input';
 import {NgIf} from '@angular/common';
 
 /** @title Fixed sidenav */
@@ -22,6 +23,7 @@ import {NgIf} from '@angular/common';
     MatCheckboxModule,
     MatFormFieldModule,
     MatButtonModule,
+    MatInputModule,
   ],
 })
 export class SidenavFixedExample {