- Fix macro expansion

- Update to version 3.6:
* Exclude RuntimeError (or RecursionError when available) from exception wrapping.
* Fix double dollar '$$' escaping such that a double dollar is always resolved, either as an interpolation expression, or as an escape where it is substituted by a single dollar symbol. This is now consistent with Zope's handling of this character.
* Drop support for Python 3.3.
* Add support for Python 3.8.
* Add support for TAL attributes in an XML declaration tag. This fixes issue #269.
* Add support for custom exception handling for the tal:on-error statement. There is now an option on_error_handler available as a template configuration (issue #266).
* Fix issue where double '$$' escaping would affect non-interpolation expressions such as the bare '$$' (issue #265).
* Fix an issue where backslash dollar escaping would leave the backslash character still in place.
* Fix regression with translations in case of multiple nodes.
* Reset error token when rendering internal macro calls.
* Fix edge case in exception handler causing recursion. [MatthewWilkes]
* Add the automatic variable macroname that's bound to the name of the executing macro. Fixes https://github.com/malthe/chameleon/issues/238
* A tokenizer can now be configured on the template class. This is useful in the case where the template file input is modified before parsing (for example, where some tags are stripped away) such that token positions need to be offset accordingly for error locations to be rendered correctly.
* Expression errors now display source marker (previously only filename, line and column was shown).
* No longer require Python source files to import modules. [mrh1997]

- Drop the doc subpackage, not really needed
- Format with spec-cleaner and reduce some of the conditionals
- Update url