config: set changes preview

- Sets the `inccommand` option to `nosplit` to preview the changes
  before accepting them with the substitute command.
- Removes unused configuration.

Co-Authored-by: iGor milhit <igor@milhit.ch>

init.lua

@@ -237,6 +237,10 @@ vim.opt.rtp:append (vim.fn.stdpath ('data') .. '/site')
 -- Set highlight on search
 vim.o.hlsearch = true
 
+-- Preview changes when searching and substituing
+--   nosplit avoid to display the preview in a separate split
+vim.o.inccommand = "nosplit"
+
 -- Make line numbers default
 vim.wo.number = true
 
@@ -245,10 +249,6 @@ vim.opt.textwidth = 79
 -- Display the cusor column at 79+1 column
 vim.opt.colorcolumn:append('+1')
 
--- Set text formatting options
---   'a' is for autoformat
--- vim.opt.formatoptions:append('a')
-
 -- Enable mouse mode
 vim.o.mouse = 'a'