pager.h: move declarations for pager.c functions from cache.h

Signed-off-by: Elijah Newren <newren@gmail.com>
Acked-by: Calvin Wan <calvinwan@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/help.c

@@ -6,6 +6,7 @@
 #include "builtin.h"
 #include "exec-cmd.h"
 #include "gettext.h"
+#include "pager.h"
 #include "parse-options.h"
 #include "run-command.h"
 #include "config-list.h"