Add documentation for what-if-short-circuiting linter rule

[tsmallig33]

Add documentation for what-if-short-circuiting linter rule that checks for runtime values that are used to determine resource IDs from within modules.

PR for v1 of new linter rule: #14910

"what-if-short-circuiting": { "allOf": [ { "description": "Runtime values should not be used to determine resource IDs. Defaults to 'Off'. See https://aka.ms/bicep/linter/what-if-short-circuiting" }, { "$ref": "#/definitions/rule-def-level-off" } ] }