Removed outdated comment

[radarhere]

Before #7641, # initialize mode cache made sense, as it came before initialising a dictionary.

Pillow/src/PIL/ImageMode.py

Lines 44 to 49 in 17af8ec

	def getmode(mode: str) -> ModeDescriptor:
	"""Gets a mode descriptor for the given mode."""
	global _modes
	if not _modes:
	# initialize mode cache
	modes = {}

Now it doesn't make sense, as the cache is managed by @lru_cache, and the following line determining endianness has nothing to do with the cache.

Pillow/src/PIL/ImageMode.py

Lines 42 to 46 in a25a1ae

	@lru_cache
	def getmode(mode: str) -> ModeDescriptor:
	"""Gets a mode descriptor for the given mode."""
	# initialize mode cache
	endian = "<" if sys.byteorder == "little" else ">"

This PR removes the comment.