Lint split ends

[som-snytt]

If a class-module companion pair have a single end marker, ensure there are no intervening statements.

// intended
class C:
  def f = 42
  def g = 27
object C:
  def check(c: C) = assert(c.f == 42)
end C

but

// unintentionally
class C:
  def f = 42
def g = 27     // warn indentation
object C:
  def check(c: C) = assert(c.f == 42)
end C