doc: Update netbsd/README regarding curses support #4510

Job	Run time
build-dragonflybsd-latest-gcc	2m 47s
build-netbsd-latest-gcc	3m 36s
build-freebsd-latest-clang	2m 40s
build-macos-latest-clang	39s
build-openbsd-latest-clang	2m 47s
build-solaris-latest-gcc	4m 26s
build-ubuntu-latest-clang-analyzer	1m 13s
build-ubuntu-latest-clang-sanitizer	1m 1s
build-ubuntu-latest-full-featured-clang	1m 1s
build-ubuntu-latest-full-featured-gcc	50s
build-ubuntu-latest-gcc-static	52s
build-ubuntu-latest-minimal-clang	57s
build-ubuntu-latest-minimal-gcc	43s
build-ubuntu-latest-pcp	22s
lint-pcp-config	5s
lint-whitespace	4s
	24m 3s

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