This change "dims" the results from the SAGA provider when a search
is made in the toolbox, to visually push users towards picking alternative
algorithms instead.
The Processing implementation of SAGA algorithms are a constant source
of critical bugs for users, causing incorrect analysis results. There's
zero community interest in actively maintaining this provider, so we
need to take steps to push users to stop picking these algorithms
wherever alternative (QGIS/GRASS/GDAL based) equivalents exist.
And for 4.0, seriously re-consider dropping this provider from the
out of the box install. We are causing more harm then good by offering
it to users.
And add a Processing setting to allow these to be shown. When shown, they
are highlighted in red with a tooltip explaining that the algorithm
has known issues
For the c++ api dox this expands to "\c nullptr" (the
\c directive indicates a code literal value), and for sipify/Python
it expands to ``None`` (`` is sphinx annotation for literal values)
Makes for nicer dox for both c++ and Python!
