Implement preimage for ceil and round functions #20197

@devanshu0987 it seems like a similar technique could be used for ceil -- if you agree I will file a ticket to track

Hi @alamb , I would like to attempt this technique for the following functions

• ceil and round
  • ceil(x) = 5 -> (4, 5]
  • round(x) = 5 -> [4.5, 5.5)
• String Prefix Functions
  • left(s, 2) = 'AB' -> Lexicographically ['AB', 'AC')
    • Not sure if this is already implemented.
    • Not sure how complex this will be for Non latin strings etc.

Originally posted by @devanshu0987 in #20099 (comment)