Merge pull request #3 from bobthecow/fish-three

Make stderr redirection compatible with Fish 3.0.

fish_prompt.fish

@@ -4,7 +4,7 @@
 #   set -g theme_display_git_untracked no
 
 function _git_branch_name
-  echo (command git symbolic-ref HEAD ^/dev/null | sed -e 's|^refs/heads/||')
+  echo (command git symbolic-ref HEAD 2> /dev/null | sed -e 's|^refs/heads/||')
 end
 
 function _is_git_dirty
@@ -13,7 +13,7 @@ function _is_git_dirty
   if [ "$theme_display_git_untracked" = 'no' -o "$show_untracked" = 'false' ]
     set untracked '--untracked-files=no'
   end
-  echo (command git status -s --ignore-submodules=dirty $untracked ^/dev/null)
+  echo (command git status -s --ignore-submodules=dirty $untracked 2> /dev/null)
 end
 
 function fish_prompt