codegen: Add codegen error (#841)

* codegen: Add codegen error

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* codegen: Use codegen error instead of aborts

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* codegen: Remove `proc-macro-error` dependency

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* macro/subxt: Transform codegen error into compile_error!

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* cli: Pretty printing for `CodegenError`

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* Update cargo.lock

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* tests: Adjust testing for codegen error

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* codegen: Fix documentation example

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* codegen: Export `CodegenError`

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* codegen: Use collect::<Result<_>, _>()

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* cli: Adjust comment regarding error printing

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* codegen: Improve error messages

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

---------

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

codegen/Cargo.toml

@@ -18,7 +18,6 @@ darling = "0.14.3"
 frame-metadata = "15.0.0"
 heck = "0.4.1"
 proc-macro2 = "1.0.51"
-proc-macro-error = "1.0.4"
 quote = "1.0.8"
 syn = "1.0.109"
 scale-info = "2.0.0"
@@ -26,6 +25,7 @@ subxt-metadata = { version = "0.27.1", path = "../metadata" }
 jsonrpsee = { version = "0.16.0", features = ["async-client", "client-ws-transport", "http-client"] }
 hex = "0.4.3"
 tokio = { version = "1.25", features = ["macros", "rt-multi-thread"] }
+thiserror = "1.0.24"
 
 [dev-dependencies]
 bitvec = { version = "1.0.0", default-features = false, features = ["alloc"] }