try adding completion in emacs

nixos/home-manager/programs/emacs/emacs.nix

@@ -3,13 +3,18 @@ let
   myEmacs = pkgs.emacs-nox;
   inherit ((pkgs.emacsPackagesFor myEmacs)) emacsWithPackages;
 in emacsWithPackages (epkgs:
-  (with epkgs.melpaStablePackages; [
-    magit
-    solarized-theme
+  (with epkgs.melpaStablePackages; [ ]) ++ (with epkgs.melpaPackages; [
+    color-theme-sanityinc-solarized
     evil
     evil-collection
-  ]) ++ (with epkgs.melpaPackages; [ xterm-color nix-mode ])
-  ++ (with epkgs.elpaPackages; [
+    helm
+    helm-projectile
+    helm-rg
+    magit
+    nix-mode
+    projectile
+    xterm-color
+  ]) ++ (with epkgs.elpaPackages; [
     beacon # ; highlight my cursor when scrolling
     nameless # ; hide current package name everywhere in elisp code
   ]) ++ [

nixos/home-manager/programs/emacs/home.nix

@@ -14,6 +14,8 @@
 
     (set-terminal-parameter nil 'background-mode 'dark)
     (xterm-mouse-mode 1)
+    (setq custom-tab-width 2)
+    (setq indent-tabs-mode nil)
 
     (setq evil-want-integration t)
     (setq evil-want-keybinding nil)
@@ -21,9 +23,11 @@
     (when (require 'evil-collection nil t)
       (evil-collection-init))
     (evil-mode 1)
-    (setq custom-tab-width 2)
-    (setq indent-tabs-mode nil)
 
+    (require 'helm)
+    (require 'helm-config)
+
+    (require 'color-theme-sanityinc-solarized)
   '';
   programs.emacs = {
     enable = true;