Add complete mute example to README

README.md

@@ -42,7 +42,7 @@ puts output
   #=> Oops!
 ```
 
-Or use it in your test suite:
+Use it in your test suite to verify output:
 
 ```ruby
 require 'mute'
@@ -60,6 +60,15 @@ describe MyLogger do
 end
 ```
 
+Or just mute stdout completely for the whole test suite:
+
+```ruby
+# spec/spec_helper.rb
+require 'mute'
+
+Mute::IO.capture_stdout
+```
+
 ## Installation
 
 ```bash