Removing "should" from RSpec descriptions

As per http://betterspecs.org/#should specs should look like:

```
it 'does not change timings' do
```

Rather than the older convention of:

```
it 'should not change timings' do
```

Author: andyjeffries

snippets/ruby_files.cson

@@ -4,7 +4,7 @@
   'it':
     'prefix': 'it'
     'body': """
-      it "should $1" do
+      it "$1" do
         $2
       end
     """