[rcore_rgfw] Updating render resolution as well on SetWindowSize

[Crisspl]

Shouldnt we update CORE.Window.render resolution here as well? Otherwise it is never updated correctly, unless handling of window resize event updates it. Which is never on WebRGFW unfortunately since resize event handling intentionally (related to #5658 ) doesn't update any sizes.
So: if window (canvas in case of web) is only ever resized with SetWindowSize() calls, then CORE.Window.render size will always be equal to initial window size.

Explanation

In my case it was breaking scissor calls on web, after exiting "texture mode" (i.e. rendering to texture):

rcore.c:EndTextureMode:

// Reset current fbo to screen size
CORE.Window.currentFbo.width = CORE.Window.render.width;
CORE.Window.currentFbo.height = CORE.Window.render.height;
CORE.Window.usingFbo = false;

rcore.c:BeginScissorMode:

rlScissor(x, CORE.Window.currentFbo.height - (y + height), width, height);

EndTextureMode was "resetting" currentFbo size to initial window's size, so subseqent BeginScissorMode scissor would pass incorrect value as 2nd parameter to rlScissor (sometimes even negative if scissor's y+height was bigger than initial window's size).

[raysan5]

@Crisspl reading the code, it make sense but note that I do not maintain the RGFW backend, pinging @CrackedPixel for review.