EndSection returns Result<Success>

Allow it to fail. When there is an error for a section ending,
print the error pointing to the line where the section starts.

Bug: 69050941
Test: boot, init_tests
Change-Id: I1d8ed25f4b74cc9ac24d38b8075751c7d606aea8
diff --git a/init/action.h b/init/action.h
index cdfc6a0..1bfc6c7 100644
--- a/init/action.h
+++ b/init/action.h
@@ -130,7 +130,7 @@
     Result<Success> ParseSection(std::vector<std::string>&& args, const std::string& filename,
                                  int line) override;
     Result<Success> ParseLineSection(std::vector<std::string>&& args, int line) override;
-    void EndSection() override;
+    Result<Success> EndSection() override;
 
   private:
     ActionManager* action_manager_;