Update rotation value to get the desired Camera View

[RayAsh37]

Your Godot version: v3.5.stable.official [991bb6ac7]

Issue description: The rotation value mentioned(45 degrees) does not yield the desired Camera View as depicted in the example image shown in the attached screenshot.

URL to the documentation page: https://docs.godotengine.org/en/stable/getting_started/first_3d_game/03.player_movement_code.html#adding-a-camera

[RayAsh37]

I have submitted a PR #6121 Please review