website: Fix incorrect tag in building docs

Change-Id: I8c603ecd11db8317f112ac8530f76d1cb35ee40f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5-website/+/67131
Tested-by: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
1 file changed