fixes vi mode indicators for fish

modules/fish/default.nix

@@ -99,22 +99,22 @@
         switch $fish_bind_mode
           case default
             set_color --bold blue
-            echo 'N'
+            echo '[N] '
           case insert
             set_color --bold green
-            echo 'I'
+            echo '[I] '
           case replace_one
             set_color --bold green
-            echo 'R'
+            echo '[R] '
           case replace
             set_color --bold bryellow
-            echo 'R'
+            echo '[R] '
           case visual
             set_color --bold brmagenta
-            echo 'V'
+            echo '[V] '
           case '*'
             set_color --bold red
-            echo '?'
+            echo '[?] '
         end
         set_color normal
       '';