check-docs: mention gitweb specially

Like gitk, gitweb is not listed in the usual Makefile
variables and must be fed to check-docs specially. Otherwise
check-docs thinks it is documented but removed.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -2805,7 +2805,7 @@ endif
 ### Check documentation
 #
 check-docs::
-	@(for v in $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS) git gitk; \
+	@(for v in $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS) git gitk gitweb; \
 	do \
 		case "$$v" in \
 		git-merge-octopus | git-merge-ours | git-merge-recursive | \
@@ -2855,7 +2855,7 @@ check-docs::
 		documented,gitworkflows | \
 		sentinel,not,matching,is,ok ) continue ;; \
 		esac; \
-		case " $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS) git gitk " in \
+		case " $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS) git gitk gitweb " in \
 		*" $$cmd "*)	;; \
 		*) echo "removed but $$how: $$cmd" ;; \
 		esac; \