Moving to neovim 0.11, new calc, keys streamlined

Keybindings:

- <space>E (explain error) now is <space>x
- dropped <C-W>0 and following, were remainders from Emacs
- insert: <C-Del> now deletes word right of cursor

LSP:

- diagnostics popup replaced with neovim 0.11 virtual lines (much nicer)

Options:

- neo-tree width dropped, was too wide
- workspaces no longer auto open, was interfering with using neovim as
  git client or file manager

Plugins:

- replaced cmp-rpncalc with qalc.nvim (which uses the qalc cli)

lua/plugins.lua

@@ -290,7 +290,6 @@ require("lazy").setup({
       require("neo-tree").setup({
         window = {
           position = "left",
-          width = 60,
           mappings = {
             ["<tab>"] = {
               "toggle_node",
@@ -324,7 +323,7 @@ require("lazy").setup({
         mru_sort = false,
 
         -- option to automatically activate workspace when opening neovim in a workspace directory
-        auto_open = true,
+        auto_open = false,
 
         -- option to automatically activate workspace when changing directory not via this plugin
         auto_dir = true,
@@ -336,12 +335,22 @@ require("lazy").setup({
     end
   },
 
-  -- rpn calculator
-  -- also added as source to cmp
+  -- calulcation in cmp
   {
-    "PhilRunninger/cmp-rpncalc",
+    "hrsh7th/cmp-calc",
   },
 
+  -- calculate using qalc cli, call :QalcAttach or :Qalc
+  {
+    "Apeiros-46B/qalc.nvim",
+    config = function()
+      require('qalc').setup({
+        bufname = "Qalculate",
+      })
+    end,
+  },
+
+
   -- TODO, WARN, HACK, PERF, NOTE, TEST and others highlighting and searching
   {
     "folke/todo-comments.nvim",