internal/frontend: change default to 25
internal/frontend: change default to 25

Change-Id: Ifbdf7e4ed59b0281f4d663cebbeb0c5b938b9a2e
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/347590
Trust: Julie Qiu <8d32267b6b4884cf35adeaccde2b6857ae11aace@golang.org>
Run-TryBot: Julie Qiu <8d32267b6b4884cf35adeaccde2b6857ae11aace@golang.org>
Reviewed-by: Jonathan Amsterdam <e3d3698b2ccd5955e4adf250d0785062d0f9018b@google.com>

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