OpenTK.Core 5.0.0-pre.13

Changed `MarshalTk.MarshalStringArrayToAnsiStringArrayPtr` to take `ReadOnlySpan<string>` instead of `Span<string>`. (@NogginBops) Vulkan bindings changes**: Add default parameterless constructor to all Vulkan structs so that default member values can be applied (mostly to automatically set `sType`). (@NogginBops) Made the Vulkan example project render a triangle. (@NogginBops) OpenGL bindings changes**: Skip `ref readonly` for singular `Delete*()` functions. (@NogginBops) Added generated EGL bindings containing all EGL and ANGLE extensions. (@NogginBops) Fixed missing documentation on some OpenGL functions. (@NogginBops) PAL2 changes**: A lot of documentation improvements. (@NogginBops) Added `Toolkit.Window.Get/SetTransparencyMode` to support different modes for window transparency. (@NogginBops) Add `reason` parameter to `Toolkit.Shell.AllowScreenSaver`. (@NogginBops) Add `Toolkit.Shell.IsScreenSaverAllowed` to be able to check if the screen saver is disabled. (@NogginBops) Added `OpenGLGraphicsApiHints.SupportsTransparentFramebufferX11` to mark if the context values selector should look for formats that support framebuffer transparency when on X11 (framebuffer transparency is always supported on Windows and macOS). (@NogginBops) Added `ContextValues.SupportsFramebufferTransparency` to check if a particular format supports framebuffer transparency (only relevant on X11). (@NogginBops) Updated `ContextValues.DefaultValuesSelector` to handle `SupportsFramebufferTransparency`. (@NogginBops) Added `Toolkit.Uninit()` for usecases where unloading OpenTK is useful (don't call this function on application exit). (@NogginBops) Added `IPalComponent.Uninitialize()` and implemented it for every component on every platform to make `Toolkit.Uninit()` possible. (@NogginBops) win32: macOS: Implement `MacOSVulkanComponent` using MoltenVK. (@NogginBops) Made dialogs proper window sheets by default. (@NogginBops) Added `MacOSDialogComponent.Show*NoWindow` functions for showing dialogs not attached to any window. (@NogginBops) x11: Fixed glX dll resolution to be the same as before 5.0-pre.12 (@NogginBops) Fixed memory leak in `X11KeyboardComponent`. (@NogginBops) ANGLE: Switched implementation to use the generated EGL bindings. (@NogginBops)