Fix copyright notices

- Add missing copright header in conf.py.
- Fix inconsistent copyright notice line breaking.

Change-Id: Ib78f7768643069c49ff986a48a176df9fd06e891
diff --git a/pw_string/format_test.cc b/pw_string/format_test.cc
index b1756a0..6beb351 100644
--- a/pw_string/format_test.cc
+++ b/pw_string/format_test.cc
@@ -1,16 +1,16 @@
 // Copyright 2019 The Pigweed Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License"); you may not
-// use this file except in compliance with the License. You may obtain a copy
-// of the License at
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
 //
 //     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-// License for the specific language governing permissions and limitations
-// under the License.
+// License for the specific language governing permissions and limitations under
+// the License.
 
 #include "pw_string/format.h"