--help-defines: mention dump subdirectory and dump=pretty

CONTRIBUTING.md

@@ -3,7 +3,7 @@ Things to check before/while filing an issue:
 - Check if you actually suspect that there's an issue in the Haxe code. If you find yourself writing "How do I..." you may want to consider a different communication channel. Refer to http://haxe.org/community/community-support.html for more information.
 - Reduce your code to a minimal example (see http://sscce.org/). In particular avoid library dependencies: If you cannot reproduce your issue without using a specific library, it might not be a Haxe issue to begin with.
 - Check if your problems are already resolved in the Haxe development version (for builds see http://builds.haxe.org/).
-- Most targets produce readable code. If you suspect the generated code to be wrong, try checking the output. Note that you can add `-D dump=pretty` to your compilation parameters and find the code which is passed to the generators in a `dump` sub directory.
+- Most targets produce readable code. If you suspect the generated code to be wrong, try checking the output. Note that you can add `-D dump=pretty` to your compilation parameters and find the code which is passed to the generators in a `dump` subdirectory.
 
 Other remarks:
 

common.ml

@@ -263,8 +263,8 @@ module Define = struct
 		| DllExport -> ("dll_export", "GenCPP experimental linking")
 		| DllImport -> ("dll_import", "GenCPP experimental linking")
 		| DocGen -> ("doc_gen","Do not perform any removal/change in order to correctly generate documentation")
-		| Dump -> ("dump","Dump the complete typed AST for internal debugging")
-		| DumpDependencies -> ("dump_dependencies","Dump the classes dependencies")
+		| Dump -> ("dump","Dump the complete typed AST for internal debugging in a dump subdirectory - use dump=pretty for Haxe-like formatting")
+		| DumpDependencies -> ("dump_dependencies","Dump the classes dependencies in a dump subdirectory")
 		| DumpIgnoreVarIds -> ("dump_ignore_var_ids","Dump files do not contain variable IDs (helps with diff)")
 		| EraseGenerics -> ("erase_generics","Erase generic classes on C#")
 		| Fdb -> ("fdb","Enable full flash debug infos for FDB interactive debugging")