Add a "this definition has worked [ ___ ] days without modification." tag to each item

[andrew4328]

"This definition has gone [ ___ ] days without modification. YOU can prevent deprecation; contact your local RFC to learn how."

[andrew4328]

Was just browsing through "stable" interfaces that were added to docs. The set[] method for hashtables definitely needs a new type signature. So yes, we will have deprecation. This is a community issue.