[Move devex] Improve Move error messages (umbrella task)

[lxfind]

For each error message, upon seeing the error message, the developer should have a relatively clear idea on the issue and how to fix it.

Let's treat it as an umbrella task with specific issues listed as subtasks:

• [Bug] [move] [compiler] incorrect error message when using wrong operator diem/move#132
• [Bug] [compiler] confusing error message when hexadecimal word is expected diem/move#133
• Improve the error message when missing a ";" at the end of if/loop statement.
• Improve the error message when we are dropping a non-droppable object.
• [Move devex] Improve error message when missing an argument in function call? #1557