Link to SDK operating modes doc in both SDK (#1330)

* rust sdk: mention SDK operating modes

* python sdk: mention operating modes

crates/rerun/src/lib.rs

@@ -13,6 +13,13 @@
 //! - [Rust API docs](https://docs.rs/rerun/)
 //! - [Troubleshooting](https://www.rerun.io/docs/getting-started/troubleshooting)
 //!
+//! There are many different ways of sending data to the Rerun Viewer depending on what you're
+//! trying to achieve and whether the viewer is running in the same process as your code, in
+//! another process, or even as a separate web application.
+//!
+//! Checkout [SDK Operating Modes](https://www.rerun.io/docs/reference/sdk-operating-modes) for an
+//! overview of what's possible and how.
+//!
 //! If you get stuck on anything, open an issue at <https://github.com/rerun-io/rerun/issues>.
 //! You can also ask questions on the [Rerun Discord](https://discord.gg/Gcm8BbTaAj).
 //!

rerun_py/docs/gen_common_index.py

@@ -10,7 +10,6 @@
 [rerun.set_recording_id()](initialization/#rerun.set_recording_id) | Set the recording ID ...
 [rerun.connect()](initialization/#rerun.connect) | Connect to a remote Rerun Viewer on the ...
 [rerun.spawn()](initialization/#rerun.spawn) | Spawn a Rerun Viewer ...
-
 ...
 
 The Summary should look like:
@@ -164,6 +163,13 @@ def make_slug(s: str) -> str:
 * [Examples on GitHub](https://github.com/rerun-io/rerun/tree/latest/examples/python)
 * [Troubleshooting](https://www.rerun.io/docs/getting-started/troubleshooting)
 
+There are many different ways of sending data to the Rerun Viewer depending on what you're trying
+to achieve and whether the viewer is running in the same process as your code, in another process,
+or even as a separate web application.
+
+Checkout [SDK Operating Modes](https://www.rerun.io/docs/reference/sdk-operating-modes) for an
+overview of what's possible and how.
+
 # APIs
 """
     )