;tools:Shake manuals: more contributor instructions in the header comment [hledger_site#140]

Shake.hs

@@ -542,15 +542,30 @@ main = do
                            else h
         -- assume any other .m4.md files in dir are included by this one XXX not true in hledger-lib
         subfiles <- liftIO $ filter (/= src) . filter (".m4.md" `isSuffixOf`) . map (dir </>) <$> S.getDirectoryContents dir
-        let deps = [src, commonm4, commandsm4, packageversionm4, packagemandatem4] ++ subfiles
+        let deps = [src, commonm4, packageversionm4, packagemandatem4] ++ subfiles
         need deps
-        when (manual=="hledger") $ need commandmds
+        when (manual=="hledger") $ need $ commandsm4 : commandmds
         -- add the web page's heading.
         -- XXX Might be nice to do this atomically with the below, so
         -- make avoid any double refresh when watch docs with entr/livereload.
         -- But cmd Shell doesn't handle arguments containing spaces properly.
-        liftIO $ writeFile out $ unlines [
-           "<!-- " ++ "Generated by \"Shake webmanuals\" from " ++ unwords deps ++ " -->"
+        let
+          aboutmsg =
+            ["<!-------------------------------------------------------------------------"
+            ,"Don't edit this file directly."
+            ,"Instead, in the hledger repo's master branch edit the source file, one of:"
+            ] <>
+            [" hledger/Hledger/Cli/Commands/commands.m4" | manual=="hledger"] <>
+            [" hledger/Hledger/Cli/Commands/*.md"        | manual=="hledger"] <>
+            [" " <> intercalate "\n " deps
+            ,""
+            ,"If the change needs to be applied to past releases' manuals on hledger.org,"
+            ,"see https://hledger.org/DOCS.html, or ask the maintainer to help."
+            ,"-------------------------------------------------------------------------->"
+            ]
+        liftIO $ writeFile out $ unlines $
+          aboutmsg <>
+          [""
           ,"<div class=\"docversions\"></div>"
           ,""
           ,"# " ++ heading