ltrim/rtrim 2-arity functions are missing

[akond]

• I have read through the quick start and installation sections of the README.

Info

Info	Value
Operating System	Linux 5.19.0-38-generic #39~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Fri Mar 17 21:16:15 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
Geni Version	[zero.one/geni "0.0.40"]
JDK	openjdk version "1.8.0_362"
	OpenJDK Runtime Environment (build 1.8.0_362-8u362-ga-0ubuntu1~22.04-b09)
	OpenJDK 64-Bit Server VM (build 25.362-b09, mixed mode)
Spark Version	[org.apache.spark/spark-core_2.12 "3.3.2"]

Problem / Steps to reproduce

org.apache.spark.sql.functions/ltrim supports both 1- and 2-arity calls, but zero-one.geni.core.functions/ltrim does only 1-arity. The same is true for rtrim.

Let me know if you fancy a PR.