[docs,feat]: protect search history and jump list

- add `keepjumps` and `keeppatterns` modifiers to regex commands
    - update readme

lua/tidy/init.lua

@@ -1,7 +1,5 @@
 -- MP
--- These sources did all the work
+
---  1. https://vim.fandom.com/wiki/Remove_unwanted_spaces#Automatically_removing_all_trailing_whitespace
---  2. https://stackoverflow.com/a/7501902
 
 local M = {}
 
@@ -12,10 +10,10 @@ function M.tidy_up()
     local pos = vim.api.nvim_win_get_cursor( 0 )
 
     -- delete all whitespace, see source 1
-    vim.cmd[[:%s/\s\+$//e]]
+    vim.cmd[[:keepjumps keeppatterns %s/\s\+$//e]]
 
     -- delete all lines at end of buffer, see source 2
-    vim.cmd[[:silent! 0;/^\%(\n*.\)\@!/,$d]]
+    vim.cmd[[:keepjumps keeppatterns silent! 0;/^\%(\n*.\)\@!/,$d]]
 
     -- get row count after line deletion
     local end_row = vim.api.nvim_buf_line_count( 0 )

readme.md

@@ -14,3 +14,6 @@ https://user-images.githubusercontent.com/59481467/138811091-05031eb1-96fc-4915-
 Credits:
 1. [Vim Tips Wiki entry for removing unwanted spaces](https://vim.fandom.com/wiki/Remove_unwanted_spaces#Automatically_removing_all_trailing_whitespace)
 2. ib., the author of [this stack overflow answer](https://stackoverflow.com/a/7501902)
+3. [This line](https://github.com/gpanders/editorconfig.nvim/blob/ae3586771996b2fb1662eb0c17f5d1f4f5759bb7/lua/editorconfig.lua#L180)
+in [gpanders/editorconfig.nvim](https://github.com/gpanders/editorconfig.nvim) for exposing me to the `keepjumps`
+and `keeppatterns` modifiers