Problem:
'endofline' can be used to detect if a file ends of <EOL>, however
editorconfig can break this.
Solution:
Set 'endofline' during BufWritePre
Fixes: #24869
Rather than only check `editorconfig_enable` when the plugin is loaded,
check it each time the autocommand fires, so that users may enable or
disable it dynamically.
Also check for a buffer local version of the variable, so that
editorconfig can be enabled or disabled per-buffer.
