Add ChangeLog entry for previous patch

Add ChangeLog entry for previous patch

I forgot to 'git commit' the ChangeLog for the previous patch.

2021-09-08  Tom Tromey  <tom@tromey.com>

	* dwarf2/read.h (dwarf2_per_objfile::resize_symtabs): Remove.
	* dwarf2/read.c (all_comp_units_iterator, all_comp_units_range):
	New classes.
	(dwarf2_per_objfile::symtab_set_p)
	(dwarf2_per_objfile::get_symtab, dwarf2_per_objfile::set_symtab):
	Adjust to resizeable vectors.
	(dwarf2_gdb_index::expand_symtabs_matching)
	(dwarf2_base_index_functions::map_symbol_filenames)
	(dwarf2_debug_names_index::expand_symtabs_matching): Use
	all_comp_units_range.
	(dwarf2_initialize_objfile, dwarf2_build_psymtabs)
	(add_type_unit): Don't call resize_symtabs.