Rule idea: preferWhere

[nicklockwood]

Automatically convert loops with a nested if statement to a where clause:

for foo in bar {
  if foo ... {

  }
}

becomes

for foo in bar where foo ... {

}

[calda]

And maybe also the inverse, convert where to a guard:

for foo in bar where foo {
  ...
}

to

for foo in bar {
  guard foo else { continue }
  ...
}