Update search templates

Not actually using them at the moment but want to avoid the
SearchPreviewTemplate showing up as a non-system tiddler

core/templates/SearchPreviewTemplate.tid

@@ -1,4 +1,4 @@
-title: SearchPreviewTemplate
+title: $:/templates/SearchPreviewTemplate
 
 <div class="title">
 <<view title text>>

core/templates/SearchResultTemplate.tid

@@ -14,7 +14,7 @@ title: $:/templates/SearchResultTemplate
 
 <div class="tw-tiddler-frame" style="color: black; width: 400px;">
 
-<<tiddler template:SearchPreviewTemplate>>
+<<tiddler template:$:/templates/SearchPreviewTemplate>>
 
 </div>