Update documentation with binding name changes

docs/src/main/asciidoc/spring-cloud-stream.adoc

@@ -261,17 +261,17 @@ rules to avoid extra configuration.
 
 ==== Binding and Binding names
 
-Binding is an abstraction that represents a bridge between remote destinations exposed by the binder and user code,
+Binding is an abstraction that represents a bridge between sources and targets exposed by the binder and user code,
 This abstraction has a name and while we try to do our best to limit configuration required to run spring-cloud-stream applications,
-being aware of such name(s) is necessary for most cases, since binding names are part of the configuration property name for a specific binding.
+being aware of such name(s) is necessary for cases where additional per-binding configuration is required.
 
 Throughout this manual you will see examples of configuration properties such as `spring.cloud.stream.bindings.input.destination=myQueue`.
-The `input` segment in this property name example is what we refer to as _binding name_ and it could derive via several mechanisms.
+The `input` segment in this property name is what we refer to as _binding name_ and it could derive via several mechanisms.
 The following sub-sections will describe the naming conventions and configuration elements used by spring-cloud-stream to control binding names.
 
 ===== Functional binding names
 
-Unlike the explicit annotation-based support (legacy) used in the previous versions of spring-cloud-stream, the functional
+Unlike the explicit annotation-based support (legacy) used in the previous versions of spring-cloud-stream via annotations, the functional
 programming model follows a simple convention when it comes to binding names thus greatly simplifying application configuration.
 Let's look at the first example:
 
@@ -287,49 +287,36 @@ public class SampleApplication {
 }
 ----
 
-In the above example we have an application with a single function which acts as message listener. As a `Function` it has an
-input and output which happened to also be the default names used for binding names - `input` and `output`. So if for example you would want to map
-the input of this function to a remote destination (e.g., topic, queue etc) called "my-topic" you would do so with the following property:
-----
-spring.cloud.stream.bindings.input.destination=my-topic
-----
-Note how `input` is used as a segment in property name. The same goes for `output`.
-
-But what if you have multiple functions as in <<Multiple functions in a single application>> section?
-
-[source, java]
-----
-@SpringBootApplication
-public class SampleApplication {
-
-	@Bean
-	public Function<String, String> uppercase() {
-	    return value -> value.toUpperCase();
-	}
-
-	@Bean
-	public Function<String, String> lowercase() {
-	    return value -> value.toLowerCase();
-	}
-}
-----
-
-We certainly can't use `input` and `output` as names given that we actually have multiple inputs and outputs.
-For those cases the following naming convention applies:
+In the preceding example we have an application with a single function which acts as message handler. As a `Function` it has an
+input and output.
+The naming convention used to name input and output bindings is as follows:
 
 * input - `<functionName> + -in- + <index>`
 * output - `<functionName> + -out- + <index>`
 
-So if for example you would want to map the input of 'uppercase()' function to a remote destination (e.g., topic, queue etc) called "my-topic"
-you would do so with the following property:
+The `in` and `out` corresponds to the type of binding (such as _input_ or _output_).
+The `index` is the index of the input or output binding. It is always 0 for typical single input/output function,
+so it's only relevant for <<Functions with multiple input and output arguments>>.
+
+So if for example you would want to map the input of this function to a remote
+destination (e.g., topic, queue etc) called "my-topic" you would do so with the following property:
 ----
-spring.cloud.stream.bindings.uppercase-in-0.destination=my-topic
+--spring.cloud.stream.bindings.uppercase-in-0.destination=my-topic
+----
+Note how `uppercase-in-0` is used as a segment in property name. The same goes for `uppercase-out-0`.
+
+***Descriptive Binding Names***
+
+Some times to improve readability you may want to give your binding a more descriptive names (such as 'account', 'orders` etc).
+You can do it with `spring.cloud.stream.function.bindings.<binding-name>` property.
+
+For example,
+----
+--spring.cloud.stream.function.bindings.uppercase-in-0=input`
 ----
 
-And if you want to change the content-type of the output of the 'lowercase()' function you would do so with the following property.
-----
-spring.cloud.stream.bindings.lowercase-out-0.content-type=text/plain
-----
+In the preceding example you mapped and effectively renamed `uppercase-in-0` binding name to `input`. Now all configuration
+properties can refer to `input` binding name instead (e.g.,  `--spring.cloud.stream.bindings.input.destination=my-topic`).
 
 For more on properties and other configuration options please see <<Configuration Options>> section.
 
@@ -554,14 +541,14 @@ Consider the following sample, which emulates such use case by producing a finit
 @SpringBootApplication
 public static class SupplierConfiguration {
 
-	@Pollable
+	@PollableBean
 	public Supplier<Flux<String>> stringSupplier() {
 		return () -> Flux.just("hello", "bye");
 	}
 }
 ----
 
-The bean itself is annotated with `Pollable` annotation (sub-set of `@Bean`), thus signaling to the framework that although the implementation
+The bean itself is annotated with `PollableBean` annotation (sub-set of `@Bean`), thus signaling to the framework that although the implementation
 of such a supplier is reactive, it still needs to be polled.
 
 ====== Polling Configuration Properties