fix(a11y): fix contrast of keyboard shortcut labels #34168

Job	Run time
Prepare PDF build image	7s
Building user_manual HTML	3m 7s
Building admin_manual HTML	1m 14s
Building user_manual-en HTML	1m 12s
Building developer_manual HTML	1m 37s
Building user_manual PDF	2m 45s
Building admin_manual PDF	2m 41s
Check for broken links	1s
Stage and check documentation	1s
Deploy documentation for gh-pages	1s
build-deploy-summary	5s
Deploy Netlify preview	1s
	12m 52s

Provide feedback