According to the maintainer of `rustaceanvim` (see his comment [here](https://github.com/LazyVim/LazyVim/pull/2198#issuecomment-1999475044)) he says
> To pick up on this: There's a good reason rustaceanvim doesn't automatically pick up a mason.nvim installation. It will most likely be built with a different toolchain than the one your project uses, often leading to discrepancies and subtle bugs.
It's easy to configure rustaceanvim to use mason.nvim if you really want it, but I generally adhere to the YAGNI principle.
I tried locally and the removal of `rust-analyzer` from `nvim-lspconfig` doesn't
seem to have any effect on how `rustaceanvim` behaves.
I propose to remove all instances of `rust-analyzer` from `nvim-lspconfig` to avoid
any possible issues from users that don't have `rust-analyzer` installed
in their toolchain (in this case it would pick up Mason's $PATH I
believe), since they will think that since `rust-analyzer` is installed
by Mason, there shouldn't be a problem and report issues as bugs.
For example, 'buffer' source by default has group_index = 2 [1], however
if we take all the sources plus crates and run them through
cmp.config.sources() again, since it's a one-dimensional list, all
group_indexes will be reset to 1.
[1] 879e29504d/lua/lazyvim/plugins/coding.lua (L74-L80)
