Fix singular and plural search results text (#12639)

Co-authored-by: Adam Turner <9087854+aa-turner@users.noreply.github.com>

Author: hugovk

CHANGES.rst

@@ -43,6 +43,8 @@ Bugs fixed
 * #12587: Do not warn when potential ambiguity detected during Intersphinx
   resolution occurs due to duplicate targets that differ case-insensitively.
   Patch by James Addison.
+* #12639: Fix singular and plural search results text.
+  Patch by Hugo van Kemenade.
 
 Testing
 -------

sphinx/themes/basic/static/searchtools.js

@@ -115,8 +115,10 @@ const _finishSearch = (resultCount) => {
       "Your search did not match any documents. Please make sure that all words are spelled correctly and that you've selected enough categories."
     );
   else
-    Search.status.innerText = _(
-      "Search finished, found ${resultCount} page(s) matching the search query."
+    Search.status.innerText = Documentation.ngettext(
+      "Search finished, found one page matching the search query.",
+      "Search finished, found ${resultCount} pages matching the search query.",
+      resultCount,
     ).replace('${resultCount}', resultCount);
 };
 const _displayNextItem = (