Fix typos

Fixes some typos.

actioncable/lib/action_cable/channel/test_case.rb

@@ -131,7 +131,7 @@ module ActionCable
     #
     # == Specifying connection identifiers
     #
-    # You need to set up your connection manually to privide values for the identifiers.
+    # You need to set up your connection manually to provide values for the identifiers.
     # To do this just use:
     #
     #   stub_connection(user: users[:john])
@@ -212,7 +212,7 @@ module ActionCable
           @connection = ConnectionStub.new(identifiers)
         end
 
-        # Subsribe to the channel under test. Optionally pass subscription parameters as a Hash.
+        # Subscribe to the channel under test. Optionally pass subscription parameters as a Hash.
         def subscribe(params = {})
           @connection ||= stub_connection
           @subscription = self.class.channel_class.new(connection, CHANNEL_IDENTIFIER, params.with_indifferent_access)

actioncable/test/channel/stream_test.rb

@@ -193,7 +193,7 @@ module ActionCable::StreamTests
       end
     end
 
-    test "subscription confirmation should only be sent out once with muptiple stream_from" do
+    test "subscription confirmation should only be sent out once with multiple stream_from" do
       run_in_eventmachine do
         connection = open_connection
         expected = { "identifier" => { "channel" => MultiChatChannel.name }.to_json, "type" => "confirm_subscription" }