Merge #525: ci: Check rustdocs build

d5294a1 ci: Check rustdocs build (Tobin C. Harding)

Pull request description:

  Currently we are not failing the docs build in CI if any warnings are generated.

  Exit the script with error code 1 if docs build throws any warnings.

ACKs for top commit:
  apoelstra:
    ACK d5294a1

Tree-SHA512: cf8a8feda8cbb4ea741b31cd0fa0e728724c60fb688f4fafcd132e93ec1a278093c64d34bfcc7e692cc80d0871b71656fc83b670a59b5f3b76c4b8fc3815d200

Author: apoelstra

contrib/test.sh

@@ -60,7 +60,7 @@ fi
 
 # Build the docs if told to (this only works with the nightly toolchain)
 if [ "$DO_DOCS" = true ]; then
-    RUSTDOCFLAGS="--cfg docsrs" cargo rustdoc --features="$FEATURES" -- -D rustdoc::broken-intra-doc-links
+    RUSTDOCFLAGS="--cfg docsrs" cargo rustdoc --features="$FEATURES" -- -D rustdoc::broken-intra-doc-links -D warnings || exit 1
 fi
 
 # Webassembly stuff