doc/asm: fix HTML markup
doc/asm: fix HTML markup

Change-Id: I33bde4835d3b83fafd55beea483f6236c4c62840
Reviewed-on: https://go-review.googlesource.com/c/go/+/338990
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Trust: Than McIntosh <4b2922593166fc595a9b1a408f34f5d3817fe9d2@google.com>

CAFxX/go,nawawi/go,CAFxX/go,nawawi/go,golang/go,cloudflare/go,nawawi/go,nawawi/go,golang/go,golang/go,cloudflare/go,nawawi/go,CAFxX/go,golang/go,golang/go,CAFxX/go,cloudflare/go,CAFxX/go,nawawi/go,golang/go,CAFxX/go,golang/go,CAFxX/go,nawawi/go,cloudflare/go,cloudflare/go,cloudflare/go,cloudflare/go,cloudflare/go,golang/go,CAFxX/go,nawawi/go