Apply suggestions from code review

Co-authored-by: Julien Portalier <[email protected]>

spec/std/http/server/handlers/static_file_handler_spec.cr

@@ -425,12 +425,12 @@ describe HTTP::StaticFileHandler do
     response.status_code.should eq(404)
   end
 
-  it "does not redirect directory when directory_listing=true" do
+  it "does not redirect directory when directory_listing=false" do
     response = handle HTTP::Request.new("GET", "/foo"), directory_listing: false
     response.status_code.should eq(404)
   end
 
-  it "redirect directory when directory_listing=false" do
+  it "redirect directory when directory_listing=true" do
     response = handle HTTP::Request.new("GET", "/foo"), directory_listing: true
     response.status_code.should eq(302)
     response.headers["Location"].should eq "/foo/"