Avoid using obsolete functions

[pocari]

When we run :checkhealth when neovim is at the following version, the following error will occur

neovim version

% nvim --version
NVIM v0.11.0-dev-314+g724d1110b
Build type: RelWithDebInfo
LuaJIT 2.1.1716656478
Run "nvim -V1 -v" for more info

:checkhealth result

E5009: Invalid $VIMRUNTIME: /home/pocari/usr/local/share/nvim/runtime
Error executing lua: function health#lsp#check, line 1: Vim(call):E117: Unknown function: health#report_start
stack traceback:
        [C]: in function 'call'
        ...e/pocari/usr/local/share/nvim/runtime/lua/vim/health.lua:366: in function '_check'
        [string "<nvim>"]:1: in main chunk

I have fixed it.

[prabirshrestha]

should be fixed by #1567.

Thanks for the PR!

[prabirshrestha]

Merged this PR instead as it seems to work with both vim and neovim.