[docs] convert spaces to tabs

site/content/tutorial/06-bindings/14-component-this/text.md

@@ -12,8 +12,8 @@ Now we can programmatically interact with this component using `field`.
 
 ```html
 <button on:click="{() => field.focus()}">
-    Focus field
+	Focus field
 </button>
 ```
 
-> Note that we can't do `{field.focus}` since field is undefined when the button is first rendered and throws an error.
+> Note that we can't do `{field.focus}` since field is undefined when the button is first rendered and throws an error.