fix: rearrange so assert(false) not on return path

[priyasiddharth]

other changes are format only

[priyasiddharth]

this change is important

[agurfinkel]

the diff is too confusing. You are replacing a return with assert. That cannot be correct.

[priyasiddharth]

The earlier code was

if (m_links.count(omni)) return *m_links.at(omni)
// else fall through to
assert(false)
// ** possibly undefined return value depending on semantics of assert **
// ** Thus, compiler complains.

Now it is rewritten such that intent is clearer and we pass the compiler check

assert(m_links.count(omni))
// ** possibly incorrect return value if assert is nop. However, **
// ** based on existing logic, we expect the assert to never fail **
return *m_links.at(omni)

[priyasiddharth]

important: braces around scalar initializer removed