Improve the docs and guide on flow cancellation (#2043)
* Improve the docs and guide on flow cancellation
* Remove outdated phrase on "flow infrastructure does not introduce additional cancellation points". They were introduced by #2028
* Add a section on "Flow cancellation check" with examples on `Flow.cancellable()`` operator.
* Add a bit more detail in `flow` and `cancellable` docs with links to `ensureActive()`.
diff --git a/coroutines-guide.md b/coroutines-guide.md
index 0b7b842..4b3c09c 100644
--- a/coroutines-guide.md
+++ b/coroutines-guide.md
@@ -47,7 +47,7 @@
* <a name='suspending-functions'></a>[Suspending functions](docs/flow.md#suspending-functions)
* <a name='flows'></a>[Flows](docs/flow.md#flows)
* <a name='flows-are-cold'></a>[Flows are cold](docs/flow.md#flows-are-cold)
- * <a name='flow-cancellation'></a>[Flow cancellation](docs/flow.md#flow-cancellation)
+ * <a name='flow-cancellation-basics'></a>[Flow cancellation basics](docs/flow.md#flow-cancellation-basics)
* <a name='flow-builders'></a>[Flow builders](docs/flow.md#flow-builders)
* <a name='intermediate-flow-operators'></a>[Intermediate flow operators](docs/flow.md#intermediate-flow-operators)
* <a name='transform-operator'></a>[Transform operator](docs/flow.md#transform-operator)
@@ -79,6 +79,8 @@
* <a name='successful-completion'></a>[Successful completion](docs/flow.md#successful-completion)
* <a name='imperative-versus-declarative'></a>[Imperative versus declarative](docs/flow.md#imperative-versus-declarative)
* <a name='launching-flow'></a>[Launching flow](docs/flow.md#launching-flow)
+ * <a name='flow-cancellation-checks'></a>[Flow cancellation checks](docs/flow.md#flow-cancellation-checks)
+ * <a name='making-busy-flow-cancellable'></a>[Making busy flow cancellable](docs/flow.md#making-busy-flow-cancellable)
* <a name='flow-and-reactive-streams'></a>[Flow and Reactive Streams](docs/flow.md#flow-and-reactive-streams)
<!--- TOC_REF docs/channels.md -->
* <a name='channels'></a>[Channels](docs/channels.md#channels)