docs: fix outdated description for CefBrowserSettings.windowless_frame_rate

[montyc1999]

Describe the bug

In these 2 places, the docs say there is a maximum windowless framerate of 60:

• https://github.com/chromiumembedded/cef/blob/7087113239f0ef0f929a9404b2807aa65d95b79e/include/internal/cef_types.h#L577
• https://github.com/chromiumembedded/cef/blob/7087113239f0ef0f929a9404b2807aa65d95b79e/include/cef_browser.h#L817

However, that limit was removed in this commit: https://github.com/chromiumembedded/cef/commit/47f15dd307f6e02cfe1b7525de5e031ddbdf372f