improve building and releasing docs

BUILDING.md

@@ -22,22 +22,12 @@ subproject _deltachat-core-rust_:
 
 ## Generate JSON-RPC bindings
 
-To generate the JSON-RPC bindings (ex. `chat.delta.rpc.*` package)
-install the [dcrpcgen tool](https://github.com/chatmail/dcrpcgen)
-then generate the `schema.json` file:
+To generate/update the JSON-RPC bindings (ex. `chat.delta.rpc.*` package)
+install Rust tooling (read sections below) and the [dcrpcgen tool](https://github.com/chatmail/dcrpcgen)
+then generate the code running the script:
 
 ```
-# in the root of the project:
-cd ./jni/deltachat-core-rust/deltachat-rpc-server
-cargo run -- --openrpc > ../../../schema.json
-cd ../../../
-```
-
-then pass the schema file to the `dcrpcgen` tool to generate the
-code:
-
-```
-dcrpcgen java --schema schema.json -o ./src/main/java/
+./scripts/generate-rpc-bindings.sh
 ```
 
 ## Build Using Nix

RELEASE.md

@@ -3,6 +3,8 @@
 
 ## Generate APKs
 
+### Update core and translations
+
 on the command-line, in a PR called "update-core-and-stuff-DATE":
 
 1. update core:
@@ -21,12 +23,19 @@ a) Update `CHANGELOG.md`
       as `update to core 1.2.3` or `using core 1.2.3`
 
 
-2. update translations and local help:
+2. update JSON-RPC bindings:
+   ```
+   ./scripts/update-rpc-bindings.sh
+   ```
+
+3. update translations and local help:
    ```
    ./scripts/tx-pull-translations.sh
    ./scripts/create-local-help.sh  # requires deltachat-pages checked out at ../deltachat-pages
    ```
 
+### Prepare release
+
 the following steps are done in a PR called `prep-VERSION` (no leading "v"):
 
 3. Update `CHANGELOG.md`:

scripts/update-rpc-bindings.sh

@@ -0,0 +1,11 @@
+#!/bin/sh
+# you need to have dcrpcgen
+
+# generate schema.json
+ROOT_DIR=$PWD
+cd ./jni/deltachat-core-rust/deltachat-rpc-server
+cargo run -- --openrpc > "$ROOT_DIR/schema.json"
+cd "$ROOT_DIR"
+
+# generate code
+dcrpcgen java --schema schema.json -o ./src/main/java/