docs: update sample formula

Also works around bug in Jekyll where a URL with a "#" will cause links
in the same paragraph to not have their extensions replaced by using
"#" instead.

docs/Formula-Cookbook.md

@@ -59,10 +59,18 @@ class Foo < Formula
   # depends_on "cmake" => :build
 
   def install
-    system "./configure", "--prefix=#{prefix}", "--disable-debug", "--disable-dependency-tracking"
+    # ENV.deparallelize
+    system "./configure", "--disable-debug",
+                          "--disable-dependency-tracking",
+                          "--disable-silent-rules",
+                          "--prefix=#{prefix}"
     # system "cmake", ".", *std_cmake_args
     system "make", "install"
   end
+
+  test do
+    system "false"
+  end
 end
 ```
 
@@ -259,7 +267,7 @@ Check the top of the e.g. `./configure` output. Some configure scripts do not re
 
 ### Add a test to the formula
 
-Please add a [`test do`](http://www.rubydoc.info/github/Homebrew/brew/master/Formula#test-class_method) block to the formula. This will be run by `brew test foo` and the [Brew Test Bot](Brew-Test-Bot.md).
+Add a valid test to the [`test do`](http://www.rubydoc.info/github/Homebrew/brew/master/Formula&num;test-class_method) block of the formula. This will be run by `brew test foo` and the [Brew Test Bot](Brew-Test-Bot.md).
 
 The
 [`test do`](http://www.rubydoc.info/github/Homebrew/brew/master/Formula#test-class_method)