Build documentation with '--edition=2018'

Author: taiki-e

ci/dox.sh

@@ -30,11 +30,13 @@ dox() {
 
   rustdoc --verbose --target "${target}" \
           -o "target/doc/${arch}" crates/core_arch/src/lib.rs \
+          --edition=2018 \
           --crate-name core_arch \
           --library-path "target/${target}/debug/deps" \
           --cfg core_arch_docs
   rustdoc --verbose --target "${target}" \
           -o "target/doc/${arch}" crates/std_detect/src/lib.rs \
+          --edition=2018 \
           --crate-name std_detect \
           --library-path "target/${target}/debug/deps" \
           --extern cfg_if="$(ls target/"${target}"/debug/deps/libcfg_if-*.rlib)" \