Remove note about MSSQL being known to work
Remove note about MSSQL being known to work

As per https://github.com/wagtail/wagtail/issues/6393

torchbox/wagtail,jnns/wagtail,FlipperPA/wagtail,FlipperPA/wagtail,zerolab/wagtail,torchbox/wagtail,FlipperPA/wagtail,mixxorz/wagtail,torchbox/wagtail,thenewguy/wagtail,thenewguy/wagtail,mixxorz/wagtail,thenewguy/wagtail,thenewguy/wagtail,rsalmaso/wagtail,jnns/wagtail,rsalmaso/wagtail,kaedroho/wagtail,gasman/wagtail,wagtail/wagtail,kaedroho/wagtail,thenewguy/wagtail,zerolab/wagtail,FlipperPA/wagtail,kaedroho/wagtail,gasman/wagtail,wagtail/wagtail,rsalmaso/wagtail,jnns/wagtail,mixxorz/wagtail,wagtail/wagtail,mixxorz/wagtail,kaedroho/wagtail,zerolab/wagtail,torchbox/wagtail,rsalmaso/wagtail,zerolab/wagtail,zerolab/wagtail,mixxorz/wagtail,gasman/wagtail,jnns/wagtail,gasman/wagtail,kaedroho/wagtail,wagtail/wagtail,gasman/wagtail,rsalmaso/wagtail,wagtail/wagtail