Fix for Issue 847 (debugger)

[cjbarre]

What has Changed?

• A small bit of increment/decrement logic has been changed while debugging the test case to produce the desired result. Also brought up a bit of nested logic which checks if syntax quote is ending via ~ or ~@ to the top level of the for loop.
• Tests have been added for other syntax quoted data structured with ~ unquote forms within.
• Light refactoring in the form of extracting a few named functions to help readability in the future.

It would be helpful if anyone could come up with some more advanced test cases for syntax quoted forms and the debugger.

Fixes 847

My Calva PR Checklist

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The Calva Team PR Checklist:

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Ping @PEZ, @kstehn, @cfehse, @bpringe

[bpringe]

Will review/test this week! Thanks Cameron 💪