add B<--nolinenumber>

[john-peterson]

I use --pager="vim - -R" and my whole work flow revolves around copying
and moving lines and blocks. hence littering makes no sense I need clean
lines

plus I use touch input so minute fiddling is a night mare

[n1vux]

Thank you. But.

This PR is literally just the easy 10% of adding such an option.

No PR without tests in ./t/ demonstrating and constraining the feature would be merged.

An over-the-wall PR without tests and unconnected to the prior conversation of a previously proposed feature ( #142 #311 PR #351 ) is not nearly as helpful as the submitter likely imagines.
Not following project style on naming of commandline parameters means even the untested code in this PR is not even a suitable base to build tests upon.
Ack house style expects negative options to be reversible, as options can be in ENV or .ackrc, so adding say --no-lineno requires a --lineno option to restore the default (short of --noenv).

After Andy finishes migrating the end-to-end (command-line) tests into YAML declarative tests (underway now), creating the additional test cases will be much easier and will lower the effort of doing the real work of testing this seemingly trivial (and nice-to-have) feature.

Note: I am in favor of this feature, as seen on prior threads, and would use it myself when I want the filenames but not the line-no's in the output.
(I will probably eventually write the tests in new style in order to make something like what is discussed in 142, 311 , full orthogonality of options and testing in combinations.)

[petdance]

Note: There will always be Perl tests. The YAMLization is just for making the tests more flexible.