Implement validation error generation for $eq, $lt, $lte, $gt, $gte, $ne, $in, and $nin along with unit tests verifying that generated errors conform to the expected format. Since this is the first ticket which tracks work for generating errors, the following will also be implemented under this ticket:

• Introduce an 'ErrorAnnotation' type for MatchExpressions
• General support for generating errors for path accepting expressions. This includes:
  • Generating errors for operators which expect a path but the path doesn't exist.
  • Appending 'consideredValues' when the operator makes use of implicit array traversal and appending 'consideredValue' when dealing with a single value.