`construct_runtime`: support for expanding the macro code (#14379)

* construct_runtime: support for expanding the macro code

* Update frame/support/procedural/src/construct_runtime/mod.rs

Co-authored-by: Bastian Köcher <git@kchr.de>

* Update frame/support/procedural/Cargo.toml

Co-authored-by: Bastian Köcher <git@kchr.de>

* fmt added

* fmt removed

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Co-authored-by: Bastian Köcher <git@kchr.de>