der

Revert "der: add `Error::(set_)source`; remove `Clone` + `Copy` (#132… #2769

Job	Run time
build (1.71.0, thumbv7em-none-eabi)	1m 44s
derive (1.71.0)	32s
build (1.71.0, wasm32-unknown-unknown)	1m 42s
derive (stable)	28s
build (stable, thumbv7em-none-eabi)	1m 27s
minimal-versions	0s
build (stable, wasm32-unknown-unknown)	1m 27s
test (i686-unknown-linux-gnu, ubuntu-latest, 1.71.0, sudo apt update && sudo apt install gcc-mult...	11m 4s
test (i686-unknown-linux-gnu, ubuntu-latest, stable, sudo apt update && sudo apt install gcc-mult...	10m 30s
test (x86_64-unknown-linux-gnu, ubuntu-latest, 1.71.0)	11m 7s
test (x86_64-unknown-linux-gnu, ubuntu-latest, stable)	9m 47s
	49m 48s

Provide feedback