Simplify the description for room versions
Simplify the description for room versions

Instead of trying to describe maturity, stability, and recommendedness in one list we should describe what is "safe" and "unsafe" to use. The default version is just something that servers should use, and is normally going to be stable.
matrix-org/matrix-doc,matrix-org/matrix-doc,matrix-org/matrix-doc,matrix-org/matrix-doc