Fixed reward description of PointMaze dense environments

[HridayM25]

Description

Fixed error in the reward description of the PointMaze env.

Type of change

Please delete options that are not relevant.

• Documentation only change (no code changed)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• I have run the pre-commit checks with pre-commit run --all-files (see CONTRIBUTING.md instructions to set it up)
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[Kallinteris-Andreas]

For reference:

Gymnasium-Robotics/gymnasium_robotics/envs/maze/maze_v4.py

Lines 375 to 382 in 2714761

	def compute_reward(
	self, achieved_goal: np.ndarray, desired_goal: np.ndarray, info
	) -> float:
	distance = np.linalg.norm(achieved_goal - desired_goal, axis=-1)
	if self.reward_type == "dense":
	return np.exp(-distance)
	elif self.reward_type == "sparse":
	return (distance <= 0.45).astype(np.float64)