Add "auto generation" comments/warning is docs that are copied/generated

[zepumph]

I was just updating doc and I ended up updating md files in community/doc/info-sync AND in phetsims/phet-info. It isn't clear to me if I should commit both, or if one is just copied from the other. My guess is something of a copy/syncing script. Can we add an md comment to the top of files that are copied so that it clear how to maintain doc in community?

[brettfiedler]

Updating the file in phetsims/phet-info will automate a GitHub Action sync task that creates a pull request to update scenerystack/community/doc/info-sync.

Our ideal (pending discussion next week), is to eliminate the need for that sync task by moving all currently synced docs to this repo. I believe only one or two files are currently affected like the Software Design Patterns doc.

I'll leave this issue open to make sure it's documented if we do for some reason retain the need for a sync.

[brettfiedler]

Example based on the commit @zepumph made: #134