info: show correct file origin for formula from path or url

Closes Homebrew/homebrew#36733.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

Library/Homebrew/cmd/info.rb

@@ -65,13 +65,14 @@ module Homebrew
     if f.tap?
       user, repo = f.tap.split("/", 2)
       path = f.path.relative_path_from(HOMEBREW_LIBRARY.join("Taps", f.tap))
-    else
-      user = f.path.parent.cd { github_fork }
-      repo = "homebrew"
-      path = f.path.relative_path_from(HOMEBREW_REPOSITORY)
-    end
-
       "https://github.com/#{user}/#{repo}/blob/master/#{path}"
+    elsif f.core_formula?
+      user = f.path.parent.cd { github_fork }
+      path = f.path.relative_path_from(HOMEBREW_REPOSITORY)
+      "https://github.com/#{user}/homebrew/blob/master/#{path}"
+    else
+      f.path
+    end
   end
 
   def info_formula f