plugins/completion: move to by-name

- Move nvim-cmp to plugins/cmp
- Move other completion plugins to plugins/by-name

plugins/by-name/copilot-vim/default.nix

@@ -0,0 +1,83 @@
+{
+  lib,
+  helpers,
+  pkgs,
+  ...
+}:
+with lib;
+with helpers.vim-plugin;
+helpers.vim-plugin.mkVimPlugin {
+  name = "copilot-vim";
+  originalName = "copilot.vim";
+  globalPrefix = "copilot_";
+
+  maintainers = [ maintainers.GaetanLepage ];
+
+  # TODO introduced 2024-03-02: remove 2024-05-02
+  deprecateExtraConfig = true;
+  optionsRenamedToSettings = [
+    "nodeCommand"
+    "filetypes"
+    "proxy"
+  ];
+
+  settingsOptions = {
+    node_command = mkOption {
+      type = with types; nullOr str;
+      default = "${pkgs.nodejs-18_x}/bin/node";
+      description = "Tell Copilot what `node` binary to use.";
+    };
+
+    filetypes = mkOption {
+      type = with types; nullOr (attrsOf bool);
+      default = null;
+      description = "A dictionary mapping file types to their enabled status.";
+      example = {
+        "*" = false;
+        python = true;
+      };
+    };
+
+    proxy = mkOption {
+      type = with types; nullOr str;
+      default = null;
+      description = ''
+        Tell Copilot what proxy server to use.
+
+        If this is not set, Copilot will use the value of environment variables like
+        `$HTTPS_PROXY`.
+      '';
+      example = "localhost:3128";
+    };
+
+    proxy_strict_ssl = helpers.mkNullOrOption types.bool ''
+      Corporate proxies sometimes use a man-in-the-middle SSL certificate which is incompatible
+      with GitHub Copilot.
+      To work around this, SSL certificate verification can be disabled by setting this option to
+      `false`.
+
+      You can also tell `Node.js` to disable SSL verification by setting the
+      `$NODE_TLS_REJECT_UNAUTHORIZED` environment variable to `"0"`.
+    '';
+
+    workspace_folders = helpers.mkNullOrOption (with types; listOf str) ''
+      A list of "workspace folders" or project roots that Copilot may use to improve to improve
+      the quality of suggestions.
+
+      Example: ["~/Projects/myproject"]
+
+      You can also set `b:workspace_folder` for an individual buffer and newly seen values will be
+      added automatically.
+    '';
+  };
+
+  settingsExample = {
+    filetypes = {
+      "*" = false;
+      python = true;
+    };
+    proxy = "localhost:3128";
+    proxy_strict_ssl = false;
+    workspace_folders = [ "~/Projects/myproject" ];
+  };
+}