This note was made while assisting a student with parse_json(…) in instructor office hours
on 11/7/2022.  It is being shared here for fairness.

When parse_element(…) is called from parse_json(…), there are three possibilities:

parse_element returns true
    (1) ... with NO trailing non-whitespace characters
        └▶ parse_json returns (ParseResult) { .is_success = true, … }
    (2) ... WITH trailing non-whitespace characters
        └▶ parse_json returns (ParseResult) { .is_success = false, … }
(3) parse_element returns false
    ├▶ don't try to access .type or .as_▒▒▒ fields since they are uninitialized
    └▶ parse_json returns (ParseResult) { .is_success = false, … }