hhctrl.ocx: Make AppendFullPathURL() static.

dlls/hhctrl.ocx/help.c

diff --git a/dlls/hhctrl.ocx/help.c b/dlls/hhctrl.ocx/help.c
index 4c6196e..61d90f6 100644
--- a/dlls/hhctrl.ocx/help.c
+++ b/dlls/hhctrl.ocx/help.c
@@ -111,7 +111,7 @@
     return ret;
 }
 
-BOOL AppendFullPathURL(LPCWSTR file, LPWSTR buf, LPCWSTR index)
+static BOOL AppendFullPathURL(LPCWSTR file, LPWSTR buf, LPCWSTR index)
 {
     static const WCHAR url_format[] =
         {'m','k',':','@','M','S','I','T','S','t','o','r','e',':','%','s',':',':','%','s','%','s',0};