content: search result width complies with style guide
content: search result width complies with style guide

Fixes b/137773464

Change-Id: I41866709b2c78086f8b331c807bbc611ee4117ff
Reviewed-on: https://team-review.git.corp.google.com/c/golang/discovery/+/509862
Reviewed-by: Julie Qiu <e6cb64861edcc38971590ff27c111e0e672de045@google.com>

golang/pkgsite,golang/pkgsite,golang/pkgsite,golang/pkgsite