Fix comment typos

When looking at PR113410, I found a comment typo and just searched for
the same typo elsewhere and found some typos in the comments which had
that typo as well.

2024-01-17  Jakub Jelinek  <jakub@redhat.com>

	* tree-into-ssa.cc (pass_build_ssa::gate): Fix comment typo,
	funcions -> functions, and use were instead of was.
	* gengtype.cc (dump_typekind): Fix comment typos, funcion -> function
	and guaranteee -> guarantee.
	* attribs.h (struct attr_access): Fix comment typo funcion -> function.