Both the definition and implementation of the != operator
have been removed from the RGBColor class because C++20
automatically generates the != operator from the == operator.
Change-Id: Ia84fa254d1d11d127f55b79f213eb64789269c7d
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/206183
Tested-by: Jenkins
Reviewed-by: Ilmari Lauhakangas <ilmari.lauhakangas@libreoffice.org>
Jason Whitmore
cb080d12c1