patch 8.1.2238: error in docs tags goes unnoticed

Problem:    Error in docs tags goes unnoticed.
Solution:   Adjust tags build command. (Ken Takata, closes #5158)
diff --git a/Filelist b/Filelist
index a2b9f0a..6cb5f63 100644
--- a/Filelist
+++ b/Filelist
@@ -663,6 +663,7 @@
 		runtime/doc/*.txt \
 		runtime/doc/Makefile \
 		runtime/doc/doctags.c \
+		runtime/doc/doctags.vim \
 		runtime/doc/test_urls.vim \
 		runtime/doc/vim.1 \
 		runtime/doc/evim.1 \