Fix #6605: Remove soft-wrap.enable option wrapping.

[gibbz00]

No description provided.

[archseer]

(Had to revert in master, @pascalkuthe pointed out a subtle bug with config override handling)

[pascalkuthe]

This is not the right fix for the problem. Softwrap can be configured both per language and globally. The language configuration takes precedence over the global config.

Therefore all softwrap options are options so that we can fallback to the global config.

With this PR the following language config would disable softwrap for markdown even if softwrap is globally enabled:

[[language]]
name ="markdown"
softwrap.wrap-at-text-width = true

In this case there is a language specific softwrap so if softwrap.enable defaults to false this would overwrite the global softwrap.enable setting.

To fix #6605 twe should either add a spegifal case to the default implementation of edit::Config to use Some(false) or make :toggle assume false if it encounters null (the former is probably better since some options default to true)