How PyF can handle trimming whitespaces in front of multiline

PyFTrim.hs

-- Solution 0, do nothing
let foo = [fmt|\
     this
       is
     a
     |]
    
-- Will return "    this\n      is\n    a\n    "

-- Solution 1, trim common alignement
let foo = [fmt|\
     this
       is
     a
     |]
    
-- Will return "this\n  is\na\n" after detecting that 4 spaces is common to all lines.
-- Limitations:
--   - Last line need to be indented
--   - You cannot have lines starting with spaces

-- Solution 2, trim based on the template haskell marker
let foo = [fmt|\
              this
                is
              a
          |]
    
-- Will return "this\nis\na\n" after removing a fixed number of space based on the position of the | in the quasiquotation
-- Limitations:
--   - difficult to see

-- Solution 3, add a marker:
let foo = [fmt|\
              |this
              | is
              |a
          |]