nvim: add rust-tools.nvim

.config/nvim/lua/blake/plugins.lua

@@ -103,6 +103,23 @@ return require('packer').startup({function()
          end
       }
    }
+   use { -- rust-tools:                make nvim a better rust environment
+      'simrat39/rust-tools.nvim',
+      config = function ()
+         local rt = require("rust-tools")
+
+         rt.setup({
+            server = {
+               on_attach = function(_, bufnr)
+                  -- Hover actions
+                  vim.keymap.set("n", "K", rt.hover_actions.hover_actions, { buffer = bufnr })
+                  -- Code action groups
+                  vim.keymap.set("n", "<Leader>a", rt.code_action_group.code_action_group, { buffer = bufnr })
+               end,
+            },
+         })
+      end
+   }
    use { -- ts-context-commentstring:  set commentstring based on context from treesitter (two langs in one file)
       'JoosepAlviste/nvim-ts-context-commentstring',
       requires = 'nvim-treesitter/nvim-treesitter',