Revert "Replace colons with dashes in internal URL paths"

This reverts commit d51a6f9042.

lib/docs/filters/core/normalize_paths.rb

@@ -34,7 +34,6 @@ module Docs
 
     def normalize_path(path)
       path = path.downcase
-      path.gsub! ':', '-'
 
       if path == '.'
         'index'

test/lib/docs/filters/core/normalize_paths_test.rb

@@ -55,10 +55,6 @@ class NormalizePathsFilterTest < MiniTest::Spec
     it "returns 'test' with 'test.html'" do
       assert_equal 'test', filter.normalize_path('test.html')
     end
-
-    it "returns 'te-st' with 'te:st'" do
-      assert_equal 'te-st', filter.normalize_path('te:st')
-    end
   end
 
   before do