This introduces two new functions `vim.keymap.set` & `vim.keymap.del`
differences compared to regular set_keymap:
- remap is used as opposite of noremap. By default it's true for <Plug> keymaps and false for others.
- rhs can be lua function.
- mode can be a list of modes.
- replace_keycodes option for lua function expr maps. (Default: true)
- handles buffer specific keymaps
Examples:
```lua
vim.keymap.set('n', 'asdf', function() print("real lua function") end)
vim.keymap.set({'n', 'v'}, '<leader>lr', vim.lsp.buf.references, {buffer=true})
vim.keymap.set('n', '<leader>w', "<cmd>w<cr>", {silent = true, buffer = 5 })
vim.keymap.set('i', '<Tab>', function()
return vim.fn.pumvisible() == 1 and "<C-n>" or "<Tab>"
end, {expr = true})
vim.keymap.set('n', '[%', '<Plug>(MatchitNormalMultiBackward)')
vim.keymap.del('n', 'asdf')
vim.keymap.del({'n', 'i', 'v'}, '<leader>w', {buffer = 5 })
```
