[docs] update edit page in getting-started (#11463)

Author: mtliendo

contributors.yml

@@ -75,6 +75,7 @@
 - ericschn
 - faergeek
 - FilipJirsak
+- focusotter
 - frontsideair
 - fyzhu
 - fz6m
@@ -179,6 +180,7 @@
 - modex98
 - morleytatro
 - ms10596
+- mtliendo
 - ned-park
 - nilubisan
 - Nismit

docs/start/tutorial.md

@@ -768,14 +768,14 @@ export default function EditContact() {
           aria-label="First name"
           type="text"
           name="first"
-          defaultValue={contact.first}
+          defaultValue={contact?.first}
         />
         <input
           placeholder="Last"
           aria-label="Last name"
           type="text"
           name="last"
-          defaultValue={contact.last}
+          defaultValue={contact?.last}
         />
       </p>
       <label>
@@ -784,7 +784,7 @@ export default function EditContact() {
           type="text"
           name="twitter"
           placeholder="@jack"
-          defaultValue={contact.twitter}
+          defaultValue={contact?.twitter}
         />
       </label>
       <label>
@@ -794,14 +794,14 @@ export default function EditContact() {
           aria-label="Avatar URL"
           type="text"
           name="avatar"
-          defaultValue={contact.avatar}
+          defaultValue={contact?.avatar}
         />
       </label>
       <label>
         <span>Notes</span>
         <textarea
           name="notes"
-          defaultValue={contact.notes}
+          defaultValue={contact?.notes}
           rows={6}
         />
       </label>