tracking: consolidate function overloads

[iuioiua]

Consolidating and simplifying function overloads makes functions easier to understand (in most cases) and reduces the documentation required for a given function (JSDocs are needed for each overload). This issue aims to track the moving of functions across the codebase to be made simpler.

For a working example of how this is done, see #3818. Potential targets:

• deepMerge()
• Various functions within std/assert

Related #3764

[iuioiua]

Closing as Yoshiya is not in favour of this idea.