nvim: Switch to mini operators plugin

Removed vim-exchange which, while an amazing functionality, is also
exactly replicated in mini.nvim (along with even more operators).

Uses slightly different mapping - not `cx<movement>` anymore but
`gx<movement>`. But this actually makes sense and fits in well with
my other g-prefixed operators (`gc` for comment and `ga` for align).

It is also the prefix for the other additional operators supplied
by mini.operators: `gs` for sorting text, `gm` for multiplying,
`gr` for replacing, `g=` for evaluating.

nvim/.config/nvim/lua/plugins/config/mini.lua

@@ -1,3 +1,4 @@
+-- automatic callback to invoke 'mini.base16' when colorscheme file is changed
 local colorsfile = vim.fn.stdpath("state") .. "/colorscheme.lua"
 local function source_colors()
 	if vim.fn.filereadable(colorsfile) == 1 then
@@ -33,7 +34,8 @@ require("mini.indentscope").setup({
 })
 
 require("mini.map").setup()
-require("mini.move").setup() -- has not hit stable yet
+require("mini.move").setup()
+require("mini.operators").setup()
 require("mini.pairs").setup()
 require("mini.trailspace").setup()
 

nvim/.config/nvim/lua/plugins/editing.lua

@@ -1,9 +1,4 @@
 return {
-	-- adds exchange operator with cx. common use: cxiw . on 2 words to switch
-	{
-		"tommcdo/vim-exchange",
-		event = "InsertEnter",
-	},
 	-- Align tables and other alignable things
 	{
 		"junegunn/vim-easy-align",