fix(docs): match DocSearch style with site theme

ref https://github.com/neovim/neovim.github.io/commit/2b4f9e47809c16743f7d31d0dc1f1e3c2f313a56

runtime/doc/pattern.txt

@@ -72,7 +72,7 @@ N			Repeat the latest "/" or "?" [count] times in
 			command "/\<keyword\>".  |exclusive|
 			'ignorecase' is used, 'smartcase' is not.
 							*v_star-default*
-			In Visual mode, search forward for the current selection.
+{Visual}*		In Visual mode, search forward for the current selection.
 			|default-mappings|
 
 							*#*
@@ -81,7 +81,7 @@ N			Repeat the latest "/" or "?" [count] times in
 			backspace, try using "stty erase <BS>" before starting
 			Vim (<BS> is CTRL-H or a real backspace).
 							*v_#-default*
-			In Visual mode, search backward for the current selection.
+{Visual}#		In Visual mode, search backward for the current selection.
 			|default-mappings|
 
 							*gstar*

scripts/gen_help_html.lua

@@ -709,16 +709,17 @@ local function gen_one(fname, to_fname, old, commit, parser_path)
     <meta http-equiv="X-UA-Compatible" content="IE=edge">
     <meta name="viewport" content="width=device-width, initial-scale=1">
     <meta name="description" content="Neovim user documentation">
+
+    <!-- algolia docsearch https://docsearch.algolia.com/docs/docsearch-v3/ -->
+    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/@docsearch/css@3" />
+    <link rel="preconnect" href="https://X185E15FPG-dsn.algolia.net" crossorigin />
+
     <link href="/css/normalize.min.css" rel="stylesheet">
     <link href="/css/bootstrap.css" rel="stylesheet">
     <link href="/css/main.css" rel="stylesheet">
     <link href="help.css" rel="stylesheet">
     <link href="/highlight/styles/neovim.min.css" rel="stylesheet">
 
-    <!-- algolia docsearch https://docsearch.algolia.com/docs/docsearch-v3/ -->
-    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/@docsearch/css@3" />
-    <link rel="preconnect" href="https://X185E15FPG-dsn.algolia.net" crossorigin />
-
     <script src="/highlight/highlight.min.js"></script>
     <script>hljs.highlightAll();</script>
     <title>%s - Neovim docs</title>