* feat(lua): vim.tbl_contains supports general tables and predicates
Problem: `vim.tbl_contains` only works for list-like tables (integer
keys without gaps) and primitive values (in particular, not for nested
tables).
Solution: Rename `vim.tbl_contains` to `vim.list_contains` and add new
`vim.tbl_contains` that works for general tables and optionally allows
`value` to be a predicate function that is checked for every key.
