Add docs

src/spectator/test_suite.cr

@@ -1,17 +1,22 @@
 module Spectator
   # Encapsulates the tests to run and additional properties about them.
+  # Use `#each` to enumerate over all tests in the suite.
   class TestSuite
     include Enumerable(Example)
 
+    # Creates the test suite.
+    # The example `group` provided will be run.
     def initialize(@group : ExampleGroup)
     end
 
-    def each
+    # Yields each example in the test suite.
+    def each : Nil
       iterator.each do |example|
         yield example
       end
     end
 
+    # Creates an iterator for the example group.
     private def iterator
       ExampleIterator.new(@group)
     end