Hotfix: check for site filters before modifying query

The previous method of removing all site filters from the search query
removed the last letter of the search. This only applies the substring
filter if any site filters are present in the query.

Fixes #306

app/templates/header.html

@@ -22,7 +22,7 @@
                             style="background-color: {{ 'var(--whoogle-dark-result-bg)' if config.dark else 'var(--whoogle-result-bg)' }} !important;
                                    color: {{ 'var(--whoogle-dark-text)' if config.dark else 'var(--whoogle-text)' }};
                             type="text" 
-                            value="{{ query[:query.find('-site:')] }}">
+                            value="{{ query[:query.find('-site:')] if '-site:' in query else query }}">
                         <input style="color: {{ 'var(--whoogle-dark-text)' if config.dark else 'var(--whoogle-text)' }}" id="search-reset" type="reset" value="x">
                         <input name="tbm" value="{{ search_type }}" style="display: none">
                         <input type="submit" style="display: none;">
@@ -54,7 +54,7 @@
                             name="q"
                             spellcheck="false"
                             type="text"
-                            value="{{ query[:query.find('-site:')] }}"
+                            value="{{ query[:query.find('-site:')] if '-site:' in query else query }}"
                             style="background-color: {{ 'var(--whoogle-dark-result-bg)' if config.dark else 'var(--whoogle-result-bg)' }} !important;
                                    color: {{ 'var(--whoogle-dark-text)' if config.dark else 'var(--whoogle-text)' }};
                                    border-bottom: {{ '2px solid var(--whoogle-dark-element-bg)' if config.dark else '0px' }};">