Update RecordableCommands.cs

[aparajit-pratap]

Purpose

Add documentation for exceptions thrown by UpdateModelValue API
Related to: https://autodesk.slack.com/archives/CL597NGH0/p1618503660006300

Declarations

Check these if you believe they are true

• The codebase is in a better state after this PR
• Is documented according to the standards
• The level of testing this PR includes is appropriate
• User facing strings, if any, are extracted into *.resx files
• All tests pass using the self-service CI.
• Snapshot of UI changes, if any.
• Changes to the API follow Semantic Versioning and are documented in the API Changes document.
• This PR modifies some build requirements and the readme is updated

FYIs

@jhauswirth

[mjkkirschner]

@aparajit-pratap can we add tests enforcing this so the docs don't go out of date without us knowing?

[mjkkirschner]

LGTM