docs: render @since versions, 0 means experimental #30649

An implication of this current approach is that `NVIM_API_LEVEL` should be
bumped when a new Lua function is added.

TODO(future): add a lint check which requires `@since` on all new functions.

ref #25416

runtime/lua/vim/secure.lua

@@ -41,6 +41,7 @@ end
 --- trusted. The user's choice is persisted in a trust database at
 --- $XDG_STATE_HOME/nvim/trust.
 ---
+---@since 11
 ---@see |:trust|
 ---
 ---@param path (string) Path to a file to read.
@@ -126,6 +127,7 @@ end
 ---
 --- The trust database is located at |$XDG_STATE_HOME|/nvim/trust.
 ---
+---@since 11
 ---@param opts vim.trust.opts
 ---@return boolean success true if operation was successful
 ---@return string msg full path if operation was successful, else error message