[needs-docs][processing] Add tooltips to input types in modeler
...to help clarify for users what the different input types mean.
Fixes#17671, which is a result of unclear distinction between
the uses of vector features vs vector layer inputs.
Tagged as needs-docs, as it may help with documentation for 3.0
ModelerParameterDefinitionDialog.PARAMETER_NUMBER: QCoreApplication.translate('Processing', 'A numeric parameter, including float or integer values.'),
ModelerParameterDefinitionDialog.PARAMETER_RASTER: QCoreApplication.translate('Processing', 'A raster layer parameter.'),
ModelerParameterDefinitionDialog.PARAMETER_TABLE: QCoreApplication.translate('Processing', 'A vector layer parameter, e.g. for algorithms which change layer styles, edit layers in place, or other operations which affect an entire layer.'),
ModelerParameterDefinitionDialog.PARAMETER_VECTOR: QCoreApplication.translate('Processing', 'A vector feature parameter, e.g. for algorithms which operate on the features within a layer.'),
ModelerParameterDefinitionDialog.PARAMETER_STRING: QCoreApplication.translate('Processing', 'A freeform string parameter.'),
ModelerParameterDefinitionDialog.PARAMETER_EXPRESSION: QCoreApplication.translate('Processing', 'A QGIS expression parameter, which presents an expression builder widget to users.'),
ModelerParameterDefinitionDialog.PARAMETER_BOOLEAN: QCoreApplication.translate('Processing', 'A boolean parameter, for true/false values.'),
ModelerParameterDefinitionDialog.PARAMETER_TABLE_FIELD: QCoreApplication.translate('Processing', 'A vector field parameter, for selecting an existing field from a vector source.'),
ModelerParameterDefinitionDialog.PARAMETER_EXTENT: QCoreApplication.translate('Processing', 'A map extent parameter.'),
ModelerParameterDefinitionDialog.PARAMETER_FILE: QCoreApplication.translate('Processing', 'A file parameter, for use with non-map layer file sources.'),
ModelerParameterDefinitionDialog.PARAMETER_POINT: QCoreApplication.translate('Processing', 'A geographic point parameter.'),
ModelerParameterDefinitionDialog.PARAMETER_CRS: QCoreApplication.translate('Processing', 'A coordinate reference system (CRS) input parameter.'),
ModelerParameterDefinitionDialog.PARAMETER_MULTIPLE: QCoreApplication.translate('Processing', 'An input allowing selection of multiple sources, including multiple map layers or file sources.'),
ModelerParameterDefinitionDialog.PARAMETER_BAND: QCoreApplication.translate('Processing', 'A raster band parameter, for selecting an existing band from a raster source.'),
ModelerParameterDefinitionDialog.PARAMETER_MAP_LAYER: QCoreApplication.translate('Processing', 'A generic map layer parameter, which accepts either vector or raster layers.')