[MINOR][PYSPARK] update _shared_params_code_gen.py

## What changes were proposed in this pull request?

1, add arg-checkings for `tol` and `stepSize` to  keep in line with `SharedParamsCodeGen.scala`
2, fix one typo

## How was this patch tested?
local build

Author: Zheng RuiFeng <ruifengz@foxmail.com>

Closes #12996 from zhengruifeng/py_args_checking.