Embed isClass and stack_frame as types

[sarahsonder]

Proposed Changes

This PR removes the isClass and stack_frame attributes and embeds them as the types .class and .frame. In addition, the input for the blank type has been changed from BLANK to .blank, and blank stack frames are now denoted by the type .blank-frame. These changes serve to streamline the process of drawing objects, classes, and stack frames while also reducing the complexity of the user input.

Type of Change

Type	Applies?
🚨 Breaking change (fix or feature that would cause existing functionality to change)	X
✨ New feature (non-breaking change that adds functionality)	X
🐛 Bug fix (non-breaking change that fixes an issue)
🎨 User interface change (change to user interface; provide screenshots)
♻️ Refactoring (internal change to codebase, without changing functionality)
🚦 Test update (change that only adds or modifies tests)	X
📚 Documentation update (change that only updates documentation)	X
📦 Dependency update (change that updates a dependency)
🔧 Internal (change that only affects developers or continuous integration)

Checklist

Before opening your pull request:

• [X] I have performed a self-review of my changes.
  • Check that all changed files included in this pull request are intentional changes.
  • Check that all changes are relevant to the purpose of this pull request, as described above.
• [X] I have added tests for my changes, if applicable.
  • This is required for all bug fixes and new features.
• [X] I have updated the project documentation, if applicable.
  • This is required for new features.
• [X] I have updated the project Changelog (this is required for all changes).

After opening your pull request:

• [x] I have verified that the CI tests have passed.
• [x] I have reviewed the test coverage changes reported by Coveralls.
• [x] I have requested a review from a project maintainer.

[coveralls]

Pull Request Test Coverage Report for Build 9408747160

Details

• 11 of 11 (100.0%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.7%) to 87.519%

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Totals
Change from base Build 9376313216:	0.7%
Covered Lines:	386
Relevant Lines:	427

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💛 - Coveralls