[doc] Documenting operators by name

[Grinnz]

perlop is organized by type of operator, and not name of operator. This makes it difficult to search visually or programmatically for a specific operator by name (symbolic or alphabetic). Three options come to mind:

1. Restructuring perlop by operator name. Quite disruptive and the current organization may have its own benefits.
2. Adding a "by operator name" section to perlop, which then internally links to the existing section that documents each operator, similar to how https://perldoc.perl.org/perlfunc#Perl-Functions-by-Category works.
3. Adding a new documentation page which has sections by operator name similar to perlfunc and perlvar, which then links to perlop as appropriate.

The existing perlop metadata or some other metadata may be useful to autogenerate such a layout.

[khwilliamson]

I would be happy if we just mentioned the English names of operators at the principal place where they are explained.