Reworkaround clippy bug (#349)

* test documentation for all crates

* remove exact version

* oops

* exact nightly version is being set as default in the docker image, no need to mention it everywhere
15 jobs for master in 8 minutes and 31 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Check
passed #419255
linux-docker
check-std

00:01:22

passed #419256
linux-docker
check-wasm

00:01:39

 
  Workspace
passed #419257
linux-docker
build-std

00:01:50

passed #419258
linux-docker
build-wasm

00:02:52

passed #419260
linux-docker
clippy-std

00:01:12

passed #419261
linux-docker
clippy-wasm

00:01:34

passed #419262
linux-docker
fmt

00:00:15

passed #419259
linux-docker
test

00:03:29

 
  Examples
failed #419265
linux-docker
examples-clippy-std

00:00:55

failed #419266
linux-docker
examples-clippy-wasm

00:00:51

passed #419267
linux-docker
examples-contract-build

00:00:31

passed #419264
linux-docker
examples-fmt

00:00:15

passed #419268
linux-docker
examples-generate-metadata

00:03:36

passed #419263
linux-docker
examples-test

00:01:38

 
  Publish
skipped #419269
linux-docker
publish-docs
 
Name Stage Failure
failed
examples-clippy-std Examples
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#single_component_path_imports

error: aborting due to previous error

error: could not compile `dns`.

Caused by:
process didn't exit successfully: `/usr/local/rustup/toolchains/nightly-2020-03-12-x86_64-unknown-linux-gnu/bin/clippy-driver rustc --crate-name dns --edition=2018 lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type cdylib --crate-type rlib --emit=dep-info,metadata -C debuginfo=2 --cfg 'feature="default"' --cfg 'feature="ink_abi"' --cfg 'feature="std"' --cfg 'feature="test-env"' --cfg 'feature="type-metadata"' -C metadata=ecdd077b48fbc17b -C extra-filename=-ecdd077b48fbc17b --out-dir /ci-cache/ink/targets/master/examples-clippy-std/debug/deps -C incremental=/ci-cache/ink/targets/master/examples-clippy-std/debug/incremental -L dependency=/ci-cache/ink/targets/master/examples-clippy-std/debug/deps --extern ink_abi=/ci-cache/ink/targets/master/examples-clippy-std/debug/deps/libink_abi-aef48c28b6133a5b.rmeta --extern ink_core=/ci-cache/ink/targets/master/examples-clippy-std/debug/deps/libink_core-499ad1b56b06299a.rmeta --extern ink_lang=/ci-cache/ink/targets/master/examples-clippy-std/debug/deps/libink_lang-03808b3023e29e16.rmeta --extern ink_primitives=/ci-cache/ink/targets/master/examples-clippy-std/debug/deps/libink_primitives-a7ee82cbd37075dd.rmeta --extern scale=/ci-cache/ink/targets/master/examples-clippy-std/debug/deps/libparity_scale_codec-3b9f3bd8167c9b4a.rmeta --extern type_metadata=/ci-cache/ink/targets/master/examples-clippy-std/debug/deps/libtype_metadata-e1b0187845331438.rmeta -C link-dead-code` (exit code: 1)
ERROR: Job failed: exit code 1
failed
examples-clippy-wasm Examples
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#single_component_path_imports

error: aborting due to previous error

error: could not compile `dns`.

Caused by:
process didn't exit successfully: `/usr/local/rustup/toolchains/nightly-2020-03-12-x86_64-unknown-linux-gnu/bin/clippy-driver rustc --crate-name dns --edition=2018 lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type cdylib --crate-type rlib --emit=dep-info,metadata -C debuginfo=2 -C metadata=1cf678e59ca8a746 -C extra-filename=-1cf678e59ca8a746 --out-dir /ci-cache/ink/targets/master/examples-clippy-wasm/wasm32-unknown-unknown/debug/deps --target wasm32-unknown-unknown -C incremental=/ci-cache/ink/targets/master/examples-clippy-wasm/wasm32-unknown-unknown/debug/incremental -L dependency=/ci-cache/ink/targets/master/examples-clippy-wasm/wasm32-unknown-unknown/debug/deps -L dependency=/ci-cache/ink/targets/master/examples-clippy-wasm/debug/deps --extern ink_core=/ci-cache/ink/targets/master/examples-clippy-wasm/wasm32-unknown-unknown/debug/deps/libink_core-a0e702e0782d4f0e.rmeta --extern ink_lang=/ci-cache/ink/targets/master/examples-clippy-wasm/wasm32-unknown-unknown/debug/deps/libink_lang-31f81ae87835c5d4.rmeta --extern ink_primitives=/ci-cache/ink/targets/master/examples-clippy-wasm/wasm32-unknown-unknown/debug/deps/libink_primitives-3da3ddc5abf99473.rmeta --extern scale=/ci-cache/ink/targets/master/examples-clippy-wasm/wasm32-unknown-unknown/debug/deps/libparity_scale_codec-869f8c70e20e85cd.rmeta -C link-dead-code` (exit code: 1)
ERROR: Job failed: exit code 1