Update error message re: plugin ordering

[sellout]

categorifier/plugin/Categorifier/Categorify.hs

Lines 90 to 91 in 3b7220f

	| the `-fplugin` flags. (GHC installs the plugins in the /reverse/ order that
	| `-fplugin` flags are provided on the command line.)

This message needs to be updated, because the behavior was changed in GHC 9.4. Now plugins are loaded in the expected order, but we need to clarify that the existing comment still holds for older versions.

[zliu41]

Good to know!