When we emit a hint about a misspelled member name, it will slightly
aid readability if we use a fixit-hint to show the proposed
name in context within the source code (and in the future this
might support some kind of auto-apply in an IDE).

This patch adds such a hint to the C++ frontend, taking us from:

test.cc:10:15: error: 'struct foo' has no member named 'colour'; did you mean 'color'?
   return ptr->colour;
               ^~~~~~

to:

test.cc:10:15: error: 'struct foo' has no member named 'colour'; did you mean 'color'?
   return ptr->colour;
               ^~~~~~
               color

gcc/cp/ChangeLog:
	PR c++/62314
	* typeck.c (finish_class_member_access_expr): When
	giving a hint about a possibly-misspelled member name,
	add a fix-it replacement hint.

gcc/testsuite/ChangeLog:
	PR c++/62314
	* g++.dg/spellcheck-fields-2.C: New test case.

From-SVN: r235785