Binary unicode operators

[timothee]

no 
    
    
    proc `±`(x, y: int): auto = (x, y)
    let a1 = `±`(2, 3) # ok
    let a2 = 2 ± 3 # CT error
    
    
    Run

but it's unclear whether it's a good idea to support because:

  * typing it is awkward on standard keyboards, and likely requires copy paste
  * some unicode symbols may look alike (even identical depending on font)
  * compiler would have to be aware of which unicode represent operators 
(required for parsing), which is potentially subjective