Variables containing dashes are now allowed by the parser

[Baptiste Mispelon]

This was originally reported in https://code.djangoproject.com/ticket/35816#comment:19

As noted in the link above, the fix for #35816 introduced was I believe to be an unintended side-effect to the parsing rules for variable names.

The documentation for variable names [1] states that:

Variable names consist of any combination of alphanumeric characters and the underscore ("_") but may not start with an underscore, and may not be a number. The dot (".") also appears in variable sections, although that has a special meaning, as indicated below. Importantly, you cannot have spaces or punctuation characters in variable names.

My understanding is that dashes (-) do not count as alphanumeric and should therefore not be allowed in a variable name.

[1] ​https://docs.djangoproject.com/en/dev/ref/templates/language/#variables

[Hailey Johnson]

I'm relatively certain I already have a fix for this implemented somewhere, but we made a different decision on my original PR, I'll get a new one up asap :)

[Sarah Boyce <42296566+sarahboyce@…>]

In 22506b2:

Fixed #36465, Refs #35816 -- Disallowed '+' and '-' characters in template variable names.

Regression in 5183f7c287a9a5d61ca1103b55166cda52d9c647.

Thank you to Jon Banafato and Baptiste Mispelon for the report.