if expression: supress incompatible types error after indentation error

[simonvonhackewitz]

Maybe it would make sense to suppress the second error in the following example.

ex is
  arg => 42
  callWith2Args(a, b i32) => {say "$a $b"; true}
  callWith2Args(a i32)    => {panic "expected two args!"; false}
  callWith2Arg            => {panic "expected two args!"; false}

  if_with_call1 is

    # 'if' requires the condition to be in a single line, doest not allow vertically aligned arguments
    if callWith2Args arg
                     arg  // this arg is parsed as first expr in the then-block
      say "ok"            // 11. should flag an error: wrong indentation
    else
      panic "expected true"

  _ := if_with_call1

> FUZION_DISABLE_ANSI_ESCAPES=true fz /tmp/issue.fz

/tmp/issue.fz:12:7: error 1: Inconsistent indentation
      say "ok"            // 11. should flag an error: wrong indentation
------^
Indentation reference point is /tmp/issue.fz:10:5:
    if callWith2Args arg
----^
While parsing: exprs, parse stack: exprs, block, implRout, implFldOrRout, routOrField, feature, expr, exprs, block, implRout, implFldOrRout, routOrField, feature, expr, exprs, block, unit


/tmp/issue.fz:10:5: error 2: Incompatible types in branches of if expression
    if callWith2Args arg
----^^^^^^^^^^^^^^^^^^^^
                     arg  // this arg is parsed as first expr in the then-block
---------------------^^^
Incompatible result types in different branches:
block returns value of type 'i32' at /tmp/issue.fz:11:22:
                     arg  // this arg is parsed as first expr in the then-block
---------------------^^^
block returns value of type 'unit' at /tmp/issue.fz:10:5:
    if callWith2Args arg
----^

2 errors.