f17bb0d18f Remove unnecessary reference (Tobin C. Harding)
Pull request description:
`T` is a generic that implements`AsRef<PushBytes>`, it should not be a reference. This is inline with other usages of `AsRef<PushBytes>` for example in `Builder::push_slice`.
Found while working on #2003
ACKs for top commit:
apoelstra:
ACK f17bb0d18f
Tree-SHA512: 6f6ae0ba5d5010db53d9c2af107df84bc058277b2b7cc35800f4e6ed93d351838b7f101284b7d80345bee639615d27d76a2e5c4c784782c5b3e5090444defe29