feat(elixir): add elixirls code actions (#4148)

This is a refactoring of #3846  with the changes:

- Use `Lazyvim.lsp.execute` on keymaps to make everything simpler;
- Remove expandMacro. 

Closes #3846

---------

Co-authored-by: Ahmed Kamal <ahmed@moon-i.com.au>

lua/lazyvim/plugins/extras/lang/elixir.lua

@@ -9,7 +9,32 @@ return {
     "neovim/nvim-lspconfig",
     opts = {
       servers = {
-        elixirls = {},
+        elixirls = {
+          keys = {
+            {
+              "<leader>cp",
+              function()
+                local params = vim.lsp.util.make_position_params()
+                LazyVim.lsp.execute({
+                  command = "manipulatePipes:serverid",
+                  arguments = { "toPipe", params.textDocument.uri, params.position.line, params.position.character },
+                })
+              end,
+              desc = "To Pipe",
+            },
+            {
+              "<leader>cP",
+              function()
+                local params = vim.lsp.util.make_position_params()
+                LazyVim.lsp.execute({
+                  command = "manipulatePipes:serverid",
+                  arguments = { "fromPipe", params.textDocument.uri, params.position.line, params.position.character },
+                })
+              end,
+              desc = "From Pipe",
+            },
+          },
+        },
       },
     },
   },