docs(input, textarea): use a valid element for querySelector

Author: thetaPC

static/usage/v7/input/helper-error/javascript.md

@@ -9,7 +9,7 @@
 ></ion-input>
 
 <script>
-  const input = input.querySelector('ion-input');
+  const input = document.querySelector('ion-input');
 
   input.addEventListener('ionInput', (ev) => validate(ev));
   input.addEventListener('ionBlur', () => markTouched());

static/usage/v7/textarea/helper-error/javascript.md

@@ -8,7 +8,7 @@
 ></ion-textarea>
 
 <script>
-  const textarea = textarea.querySelector('ion-textarea');
+  const textarea = document.querySelector('ion-textarea');
 
   textarea.addEventListener('ionInput', (ev) => validate(ev));
   textarea.addEventListener('ionBlur', () => markTouched());

static/usage/v8/input/helper-error/javascript.md

@@ -9,7 +9,7 @@
 ></ion-input>
 
 <script>
-  const input = input.querySelector('ion-input');
+  const input = document.querySelector('ion-input');
 
   input.addEventListener('ionInput', (ev) => validate(ev));
   input.addEventListener('ionBlur', () => markTouched());

static/usage/v8/textarea/helper-error/javascript.md

@@ -8,7 +8,7 @@
 ></ion-textarea>
 
 <script>
-  const textarea = textarea.querySelector('ion-textarea');
+  const textarea = document.querySelector('ion-textarea');
 
   textarea.addEventListener('ionInput', (ev) => validate(ev));
   textarea.addEventListener('ionBlur', () => markTouched());