Revert "static/frontend/unit: unit header becomes sticky as the page is scrolled"
Revert "static/frontend/unit: unit header becomes sticky as the page is scrolled"

This reverts commit 43e917ddc9570bfa168f2c3caccf35c2565218ab.

Reason for revert: golang/go#45841

Change-Id: Ie7939536001be96d11dbe9be565243f84aeae41d
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/341430
Trust: Jamal Carvalho <e0195770807aa8c82b0b128d9c0423b5ad035172@golang.org>
Run-TryBot: Jamal Carvalho <e0195770807aa8c82b0b128d9c0423b5ad035172@golang.org>
TryBot-Result: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Jonathan Amsterdam <e3d3698b2ccd5955e4adf250d0785062d0f9018b@google.com>
Reviewed-by: Julie Qiu <8d32267b6b4884cf35adeaccde2b6857ae11aace@golang.org>

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