assets: Do not override js/search-data.json

assets/js/search-data.json

----
----
-{
-  {% for page in site.html_pages %}{% if page.search_exclude != true %}"{{ forloop.index0 }}": {
-    "id": "{{ forloop.index0 }}",
-    "title": "{{ page.title | replace: '&', '&' }}",
-    "content": "{{ page.content | markdownify | strip_html | escape_once | remove: 'Table of contents' | remove: '```'  | remove: '---' | replace: '\', ' ' | normalize_whitespace }}",
-    "url": "{{ page.url | absolute_url }}",
-    "relUrl": "{{ page.url }}"
-  }{% unless forloop.last %},{% endunless %}
-  {% endif %}{% endfor %}
-}