Parse ranged set from TLA state

[rnbguy]

Closes: #156

Description

Adds support for parsing TLA states with ranges set.

a = 1..10

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For contributor use:

• If applicable, unit tests are written and added to CI.
• Ran go fmt, cargo fmt and etc. (or had formatting run automatically on all files edited)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Re-reviewed Files changed in the Github PR explorer.
• Added a changelog entry, using unclog.

N/A:

• Updated relevant documentation (docs/) and code comments.

[rnbguy]

The set syntax is described in TLA+ summary.