PR 62314: add ability to add fixit-hints to a diagnostic

PR 62314: add ability to add fixit-hints to a diagnostic

This is the combination of two patches:
  [PATCH 01/02] PR/62314: add ability to add fixit-hints
  [PATCH 02/02] C FE: add fix-it hint for . vs ->

gcc/ChangeLog:
	PR 62314
	* diagnostic-show-locus.c (colorizer::set_fixit_hint): New.
	(class layout): Update comment
	(layout::print_any_fixits): New method.
	(layout::move_to_column): New method.
	(diagnostic_show_locus): Add call to layout.print_any_fixits.

gcc/c/ChangeLog:
	PR 62314
	* c-typeck.c (should_suggest_deref_p): New function.
	(build_component_ref): Special-case POINTER_TYPE when
	generating a "not a structure of union"  error message, and
	suggest a "->" rather than a ".", providing a fix-it hint.

gcc/testsuite/ChangeLog:
	PR 62314
	* gcc.dg/fixits.c: New file.
	* gcc.dg/plugin/diagnostic-test-show-locus-ascii-bw.c
	(test_fixit_insert): New.
	(test_fixit_remove): New.
	(test_fixit_replace): New.
	* gcc.dg/plugin/diagnostic-test-show-locus-ascii-color.c
	(test_fixit_insert): New.
	(test_fixit_remove): New.
	(test_fixit_replace): New.
	* gcc.dg/plugin/diagnostic_plugin_test_show_locus.c
	(test_show_locus): Add tests of rendering fixit hints.

libcpp/ChangeLog:
	PR 62314
	* include/line-map.h (source_range::intersects_line_p): New
	method.
	(rich_location::~rich_location): New.
	(rich_location::add_fixit_insert): New method.
	(rich_location::add_fixit_remove): New method.
	(rich_location::add_fixit_replace): New method.
	(rich_location::get_num_fixit_hints): New accessor.
	(rich_location::get_fixit_hint): New accessor.
	(rich_location::MAX_FIXIT_HINTS): New constant.
	(rich_location::m_num_fixit_hints): New field.
	(rich_location::m_fixit_hints): New field.
	(class fixit_hint): New class.
	(class fixit_insert): New class.
	(class fixit_remove): New class.
	(class fixit_replace): New class.
	* line-map.c (source_range::intersects_line_p): New method.
	(rich_location::rich_location): Add initialization of
	m_num_fixit_hints to both ctors.
	(rich_location::~rich_location): New.
	(rich_location::add_fixit_insert): New method.
	(rich_location::add_fixit_remove): New method.
	(rich_location::add_fixit_replace): New method.
	(fixit_insert::fixit_insert): New.
	(fixit_insert::~fixit_insert): New.
	(fixit_insert::affects_line_p): New.
	(fixit_remove::fixit_remove): New.
	(fixit_remove::affects_line_p): New.
	(fixit_replace::fixit_replace): New.
	(fixit_replace::~fixit_replace): New.
	(fixit_replace::affects_line_p): New.

From-SVN: r230674