Rollup merge of #142764 - ChaiTRex:ilog_10_to_ilog10, r=workingjubilee

Convert `ilog(10)` to `ilog10()`

Except in tests, convert `integer.ilog(10)` to `integer.ilog10()` for better speed and to provide better examples of code that efficiently counts decimal digits. I couldn't find any instances of `integer.ilog(2)`.

Author: Kobzol