mention that the bitwise operators also exist in two versions in modern Perl

[book]

The third paragraph of perlop says:

There are a few exceptions though: The operator x can be either string repetition or list repetition, depending on the type of the left operand, and &, |, ^ and ~ can be either string or numeric bit operations.

I think it would be worth mentioning the 'bitwise' feature there, which gives the bitwise operators a numeric and a string version, making them less of an exception in modern Perl.

@Grinnz said on IRC:

given that use v5.28 and above enable it automatically, I think it's worth explicitly calling out the different reality in modern perl

This patch is the smallest thing I could come up with, and this PR is meant to be a conversation starter to find a better wording for this.

• This set of changes does not require a perldelta entry.