Rename KeyPair to Keypair #588

Job	Run time
Cross (aarch64-unknown-linux-gnu)	1m 50s
Cross (i686-unknown-linux-gnu)	1m 40s
Cross (x86_64-pc-windows-gnu)	2m 27s
Cross (x86_64-unknown-linux-gnu)	1m 58s
Cross (aarch64-unknown-linux-musl)	1m 49s
Cross (arm-unknown-linux-gnueabi)	1m 46s
Cross (arm-unknown-linux-gnueabihf)	1m 56s
Cross (armv7-unknown-linux-gnueabihf)	1m 48s
Cross (mips-unknown-linux-gnu)	1m 59s
Cross (mips64-unknown-linux-gnuabi64)	1m 40s
Cross (mips64el-unknown-linux-gnuabi64)	2m 17s
Cross (mipsel-unknown-linux-gnu)	1m 48s
Cross (powerpc-unknown-linux-gnu)	1m 40s
Cross (powerpc64le-unknown-linux-gnu)	2m 3s
Cross (riscv64gc-unknown-linux-gnu)	1m 44s
Cross (s390x-unknown-linux-gnu)	2m 11s
Cross (x86_64-unknown-linux-musl)	1m 57s
	32m 33s

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