Move Postcard link up to Bincode spot

Bincode has been in prerelease limbo for nearly a year and the readme
does not mention anything related to Serde, so it is not serving as a
good first link to a Serde binary format.

Author: dtolnay

_src/README.md

@@ -43,8 +43,7 @@ The following is a partial list of data formats that have been implemented for
 Serde by the community.
 
 - [JSON], the ubiquitous JavaScript Object Notation used by many HTTP APIs.
-- [Bincode], a compact binary format used for IPC within the Servo rendering
-  engine.
+- [Postcard], a no\_std and embedded-systems friendly compact binary format.
 - [CBOR], a Concise Binary Object Representation designed for small message size
   without the need for version negotiation.
 - [YAML], a self-proclaimed human-friendly configuration language that ain't
@@ -57,7 +56,6 @@ Serde by the community.
 - [Avro], a binary format used within Apache Hadoop, with support for schema
   definition.
 - [JSON5], a superset of JSON including some productions from ES5.
-- [Postcard], a no\_std and embedded-systems friendly compact binary format.
 - [URL] query strings, in the x-www-form-urlencoded format.
 - [Envy], a way to deserialize environment variables into Rust structs.
   *(deserialization only)*
@@ -75,7 +73,7 @@ Serde by the community.
   *(deserialization only)*
 
 [JSON]: https://github.com/serde-rs/json
-[Bincode]: https://github.com/bincode-org/bincode
+[Postcard]: https://github.com/jamesmunns/postcard
 [CBOR]: https://github.com/enarx/ciborium
 [YAML]: https://github.com/dtolnay/serde-yaml
 [MessagePack]: https://github.com/3Hren/msgpack-rust
@@ -86,7 +84,6 @@ Serde by the community.
 [Avro]: https://github.com/flavray/avro-rs
 [JSON5]: https://github.com/callum-oakley/json5-rs
 [URL]: https://docs.rs/serde_qs
-[Postcard]: https://github.com/jamesmunns/postcard
 [Envy]: https://github.com/softprops/envy
 [Envy Store]: https://github.com/softprops/envy-store
 [Cargo]: http://doc.crates.io/manifest.html

_src/custom-serialization.md

@@ -32,7 +32,7 @@ These methods are generic over the serialization format, represented by the
 [`Serializer`](https://docs.serde.rs/serde/ser/trait.Serializer.html) and
 [`Deserializer`](https://docs.serde.rs/serde/de/trait.Deserializer.html) traits.
 For example there is one Serializer type for JSON and a different one for
-Bincode.
+Postcard.
 
 - [Implementing `Serialize`](impl-serialize.md)
 - [Implementing `Deserialize`](impl-deserialize.md)

_src/deserialize-struct.md

@@ -19,7 +19,7 @@ map](deserialize-map.md) in order to avoid allocating a String to hold the field
 names. Instead there is a `Field` enum which is deserialized from a `&str`.
 
 The implementation supports two possible ways that a struct may be represented
-by a data format: as a seq like in Bincode, and as a map like in JSON.
+by a data format: as a seq like in Postcard, and as a map like in JSON.
 
 !PLAYGROUND 2e212d29e38110fc3d8f22ff920712be
 ```rust

_src/impl-deserialize.md

@@ -46,7 +46,7 @@ kinds of deserialization.
    `Deserializer::deserialize_any`.
 
 2. The various other `deserialize_*` methods. Non-self-describing formats like
-   Bincode need to be told what is in the input in order to deserialize it. The
+   Postcard need to be told what is in the input in order to deserialize it. The
    `deserialize_*` methods are hints to the deserializer for how to interpret
    the next piece of input. Non-self-describing formats are not able to
    deserialize something like `serde_json::Value` which relies on
@@ -56,7 +56,7 @@ When implementing `Deserialize`, you should avoid relying on
 `Deserializer::deserialize_any` unless you need to be told by the Deserializer
 what type is in the input. Know that relying on `Deserializer::deserialize_any`
 means your data type will be able to deserialize from self-describing formats
-only, ruling out Bincode and many others.
+only, ruling out Postcard and many others.
 
 ## The Visitor trait
 

_src/impl-deserializer.md

@@ -13,7 +13,7 @@ indicate what Serde data model type the `Deserialize` type expects to see in the
 input. For self-describing formats like JSON, it is fine for the `Deserializer`
 to ignore this hint and just call whichever `Visitor` method corresponds to the
 content of the input data. Other formats, especially compact binary formats like
-Bincode, rely on the hint to determine how the input data is to be interpreted.
+Postcard, rely on the hint to determine how the input data is to be interpreted.
 
 Self-describing formats can save a lot of code by using the
 [`forward_to_deserialize_any!`] macro to ignore hints and forward some or all of