Doc: minor language corrections
Doc: minor language corrections

Task-number: QTBUG-35725
Change-Id: I84e47a72487b57665d0c11066cf73112a74a3529
Reviewed-by: Martin Smith <a8cc6484db2755056ccf1c457da8ca771f895dea@digia.com>
Reviewed-by: Topi Reiniö <92400b03a70fe3119347f89b476f73d34ae93598@digia.com>
Reviewed-by: Mitch Curtis <a74594a5101269175fe1b140badc4c0b6f699d25@digia.com>

kobolabs/qtdoc,kobolabs/qtdoc,kobolabs/qtdoc,kobolabs/qtdoc