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.cpp b/init/action.cpp
index 2617d00..5fa6bec 100644
--- a/init/action.cpp
+++ b/init/action.cpp
@@ -379,10 +379,12 @@
     return action_ ? action_->AddCommand(std::move(args), line) : Success();
 }
 
-void ActionParser::EndSection() {
+Result<Success> ActionParser::EndSection() {
     if (action_ && action_->NumCommands() > 0) {
         action_manager_->AddAction(std::move(action_));
     }
+
+    return Success();
 }
 
 }  // namespace init