Add lexical scope and redefining variables in functions (#3015)

* Fix to allow variable shadowing inside functions

* Implement closures

* Fix KCL test code to not reference future tag definition

* Remove tag declarator from function parameters

This is an example where the scoping change revealed a subtle issue
with TagDeclarators.  You cannot bind a new tag using a function
parameter.

The issue is that evaluating a TagDeclarator like $foo binds an
identifier to its corresponding TagIdentifier, but returns the
TagDeclarator.  If you have a TagDeclarator passed in as a parameter
to a function, you can never get its corresponding TagIdentifier.

This seems like a case where TagDeclarator evaluation needs to be
revisited, especially now that we have scoped tags.

* Fix to query return, functions, and tag declarator AST nodes correctly

src/lang/std/sketchConstraints.test.ts

@@ -363,7 +363,7 @@ const part001 = startSketchOn('XY')
     const programMemory = await enginelessExecutor(parse(code))
     const index = code.indexOf('// normal-segment') - 7
     const _segment = getSketchSegmentFromSourceRange(
-      programMemory.root['part001'] as SketchGroup,
+      programMemory.get('part001') as SketchGroup,
       [index, index]
     )
     if (err(_segment)) throw _segment
@@ -379,7 +379,7 @@ const part001 = startSketchOn('XY')
     const programMemory = await enginelessExecutor(parse(code))
     const index = code.indexOf('// segment-in-start') - 7
     const _segment = getSketchSegmentFromSourceRange(
-      programMemory.root['part001'] as SketchGroup,
+      programMemory.get('part001') as SketchGroup,
       [index, index]
     )
     if (err(_segment)) throw _segment