Improve Documentation of Non-Trivial Operations

[baierd]

Some operations in SMTLib2, for example Integer modulo() and BV smodulo() (signed modulo), behave differently. Our documentation does not reflect this properly or fails to explain the differences in a well-understandable way. Additionally, we could update the documentation of some operations that are not well understandable. We should take a closer look at our public API documentation and update it accordingly.

Examples:

• Integer modulo
• BV smodulo
• BV remainder
• BV division
• Integer modularCongruence
• Numeral division