Removal of deprecated mathtext APIs

The following matplotlib.mathtext APIs have been removed: - Fonts and all its subclasses, - FontConstantsBase and all its subclasses, - Node and all its subclasses, - Ship, ship, - Error, - Parser, - SHRINK_FACTOR, GROW_FACTOR, - NUM_SIZE_LEVELS, - latex_to_bakoma, latex_to_cmex, latex_to_standard, - stix_virtual_fonts, - tex2uni

Removal of various mathtext helpers

The following matplotlib.mathtext classes: - MathtextBackendPdf, - MathtextBackendPs, - MathtextBackendSvg, - MathtextBackendCairo, and the .mathtext_parser attributes on - RendererPdf, - RendererPS, - RendererSVG, - RendererCairo have been removed. The MathtextBackendPath class can be used instead.

The methods get_depth, parse, to_mask, to_rgba, and to_png of MathTextParser have been removed. Use mathtext.math_to_image instead.

The unused StandardPsFonts.pswriter has been removed.

ps.useafm removed for mathtext

The setting rcParams["ps.useafm"] (default: False) no longer has any effect on matplotlib.mathtext.