There are a number of UTF-8 characters in comments which add no value
and can be replaced with ASCII equivalents, or removed entirely for the
section sign (U+00A7).

	PR libstdc++/88607
	* include/bits/forward_list.h: Replace UTF-8 "ligature fi" character.
	* include/debug/forward_list: Likewise.
	* include/experimental/bits/shared_ptr.h: Remove UTF-8 "section sign"
	character.
	* include/experimental/chrono: Likewise.
	* include/experimental/functional: Likewise.
	* include/experimental/ratio: Likewise.
	* include/experimental/system_error: Likewise.
	* include/experimental/tuple: Likewise.
	* include/experimental/type_traits: Likewise.
	* include/parallel/workstealing.h: Replace UTF-8 "en dash" character.
	* include/parallel/multiseq_selection.h: Likewise.

Tested powerpc64-linux, committed to trunk.