Update src/routes/reference/components/error-boundary.mdx

Co-authored-by: Sarah <gerrardsarah@gmail.com>

Author: amirhhashemi

src/routes/reference/components/error-boundary.mdx

@@ -22,7 +22,7 @@ For instance:
 
 **Type**: `JSX.Element | ((err: any, reset: () => void) => JSX.Element)`
 
-The content to display when an error occurs.
+`fallback` provides content to display when an error occurs.
 If a function is passed, it receives two parameters:
 
 - `err`: The caught error object.