[Alias] Aliased commands retain newlines (#4656)

Co-authored-by: Michael Oliveira <34169552+Flame442@users.noreply.github.com>

redbot/pytest/core.py

@@ -23,7 +23,9 @@ __all__ = [
     "empty_role",
     "empty_user",
     "member_factory",
+    "newline_message",
     "user_factory",
+    "prefix",
     "ctx",
 ]
 
@@ -142,6 +144,18 @@ def empty_message():
     return mock_msg("No content.")
 
 
+@pytest.fixture(scope="module")
+def newline_message():
+    mock_msg = type("", (), {})()
+    mock_msg.content = "!test a\nb\nc"
+    return mock_msg
+
+
+@pytest.fixture(scope="module")
+def prefix():
+    return "!"
+
+
 @pytest.fixture()
 def ctx(empty_member, empty_channel, red):
     mock_ctx = namedtuple("Context", "author guild channel message bot")