Dyno: named declarations should report their indentation separately from their name locations

[DanilaFe]

Today, some of Dyno's AST nodes that subclass NamedDecls (and possibly others) report their location as the name of the node. Thus, in the following code, the location is reported as that of the word myVar:

var myVar = 42;
//  ^^^^^ location

This is inconsistent with other AST nodes in Dyno (the most significant example is probably modules and records, which report their location as the beginning of the keyword). Moreover, we have a mechanism in Dyno by which locations of other part of the AST node can be communicated: additional location maps, introduced by @dlongnecke-cray in #23548.

Currently, the lack of non-name location reporting causes workarounds in language tooling;

chapel/tools/chplcheck/src/rules.py

Lines 643 to 646 in 00d7194

	# some NamedDecl nodes currently use the name as the location, which
	# does not indicate their actual indentation.
	if isinstance(child, (VarLikeDecl, TupleDecl, ForwardingDecl)):
	continue

is the most significant example, and needed to be expanded in #25207.

It might be necessary to adjust error reporting code to make use of auxiliary location maps to compensate for this change.