Using 0xf10d0c ("Dark Red 1") for Spelling brings a contrast of 4.8
and 4.37:1 against white and dark respectively. 0x3465a4 ("Dark Blue 1")
for Grammar results in 5.92 / 3.54.
Change-Id: I8347c2dd68e25aea33f7f2476f6b6d2db370ee7e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/211616
Tested-by: Jenkins
Reviewed-by: Heiko Tietze <heiko.tietze@documentfoundation.org>