nvim: keymappings: Drop mapping to save

We have a keyboard macro to do this.

nvim/.config/nvim/lua/keymappings.lua

@@ -5,8 +5,6 @@ local opts      = { noremap=true, silent=true, unique=true }
 remap('c', '<Esc>', '<C-C>', opts)
 -- Use Q to execute default register.
 remap('n', 'Q', '<Nop>', opts)
--- Save
-remap('n', '<Leader>w', '<Esc>:w<CR>', opts)
 -- Copy to clipboard
 remap('v', '<Leader>y', '"+y'     , opts)
 remap('v', '<Leader>Y', '"*y'     , opts)