sdk/docs/external_refs: remove license headers, point links at new docs

The license headers have to go, since they're getting inlined into generated
docs and messing up the formatting of docs pages a bit. migration-guide.html
also gets the boot since it's not referenced anywhere.

Signed-off-by: Ruby Iris Juric <ruby@srxl.me>

sdk/docs/external_refs/UiFramework.html

@@ -1,17 +1 @@
-<!--
- Copyright 2024 Google LLC
-
- 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
-
-     http://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.
--->
-
-<a href="https://developer.getpebble.com/guides/pebble-apps/display-and-animations/layers/">User Interface Layers chapter in the Pebble Developer Guides</a>
+<a href="https://developer.rebble.io/guides/user-interfaces/layers">User Interface Layers chapter in the Pebble Developer Guides</a>

sdk/docs/external_refs/UsingResources.html

@@ -1,17 +1 @@
-<!--
- Copyright 2024 Google LLC
-
- 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
-
-     http://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.
--->
-
-<a href="https://developer.getpebble.com/guides/pebble-apps/resources/">App Resources in the Pebble Developer Guides</a>
+<a href="https://developer.rebble.io/guides/app-resources/">App Resources in the Pebble Developer Guides</a>

sdk/docs/external_refs/app-phone-communication.html

@@ -1,17 +1 @@
-<!--
- Copyright 2024 Google LLC
-
- 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
-
-     http://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.
--->
-
-<a href="http://developer.getpebble.com/guides/pebble-apps/communications/">App Communication in the Pebble Developer Guides</a>
+<a href="https://developer.rebble.io/guides/communication/index.html">App Communication in the Pebble Developer Guides</a>

sdk/docs/external_refs/migration-guide.html

@@ -1,17 +0,0 @@
-<!--
- Copyright 2024 Google LLC
-
- 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
-
-     http://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.
--->
-
-<a href="http://developer.getpebble.com/sdk/migration-guide/">2.0 Migration Guide</a>