AAPT2: Add missing description for dump command

Test: None
Bug: None
Change-Id: Id9d6a38ad292dc2647bdb4ad9f7a0015120fa776
diff --git a/tools/aapt2/cmd/Dump.h b/tools/aapt2/cmd/Dump.h
index 5cf056e..7ded9bc 100644
--- a/tools/aapt2/cmd/Dump.h
+++ b/tools/aapt2/cmd/Dump.h
@@ -32,6 +32,7 @@
  public:
   explicit DumpApkCommand(const std::string&& name, text::Printer* printer, IDiagnostics* diag)
       : Command(name), printer_(printer), diag_(diag) {
+        SetDescription("Dump information about an APK or APC.");
   }
 
   text::Printer* GetPrinter() {