Fix contain / should match confusion

[zmalone]

If attempting to use "contain" here, you get

     [UNSUPPORTED] `contain` matcher. Please use the following syntax `its('content') { should match('value') }`.

it looks like this should say "should match". This may effect other resources, but I've only tried file.

[arlimus]

Great catch, using match here is much better.

An alternative, by the way, is to use include which is not treated as a regular expression (unlike match).

describe file(...) do
  its('content') { should include 'hello...' }
end

Thank you @zmalone ! :)