New messages matching an existing translation ID are not added to the output file

[nikklassen]

Currently translation source are not updated when their value changes when using specific IDs. I would expect the extractor to behave like ngc and simply overwrite the output file (my current workaround is to delete the source file every time I run the extractor), or potentially overwriting old sources and using the state attribute to indicate that it needs translation.

I see in message-bundle.ts that there is a comment suggesting there was a plan for merging sources, so I was wondering if you could share what your thoughts were.