doctor: be more helpful with suggestion about PATH

- Show a one liner that will append to
  the user's ~/.bash_profile. In 95% this will be
  ok and we assume zsh people are smart enough
  to know what they have to do.

Library/Homebrew/cmd/doctor.rb

@@ -452,8 +452,9 @@ def check_user_path_1
 
                 #{conflicts * "\n                "}
 
-            Consider amending your PATH so that #{HOMEBREW_PREFIX}/bin
-            occurs before /usr/bin in your PATH.
+            Consider setting your PATH so that #{HOMEBREW_PREFIX}/bin
+            occurs before /usr/bin. Here is a one-liner:
+                echo export PATH="#{HOMEBREW_PREFIX}/bin:$PATH" >> ~/.bash_profile
           EOS
         end
       end
@@ -469,9 +470,9 @@ def check_user_path_1
 def check_user_path_2
   unless $seen_prefix_bin
     <<-EOS.undent
-      Homebrew's bin was not found in your path.
-      Consider amending your PATH variable so it contains:
-        #{HOMEBREW_PREFIX}/bin
+      Homebrew's bin was not found in your PATH.
+      Consider setting the PATH for example like so
+          echo export PATH="#{HOMEBREW_PREFIX}/bin:$PATH" >> ~/.bash_profile
     EOS
   end
 end
@@ -482,9 +483,10 @@ def check_user_path_3
   if sbin.directory? and sbin.children.length > 0
     unless $seen_prefix_sbin
       <<-EOS.undent
-        Homebrew's sbin was not found in your path.
-        Consider amending your PATH variable so it contains:
-          #{HOMEBREW_PREFIX}/sbin
+        Homebrew's sbin was not found in your PATH but you have installed
+        formulae that put executables in #{HOMEBREW_PREFIX}/sbin.
+        Consider setting the PATH for example like so
+            echo export PATH="#{HOMEBREW_PREFIX}/sbin:$PATH" >> ~/.bash_profile
       EOS
     end
   end