.editorconfig

sparse: properly error out when absolute paths are used

Current logic is misleading (it says it drops only absolute paths, but
it actually drops all of them), not cross-platform (does not support Windows)
and IMO just wrong (as it should just error out if absolute paths are given).

This commit fixes it.

# See http://EditorConfig.org for the specification

root = true

[*.py]
indent_size = 4
indent_style = space
trim_trailing_whitespace = true

[*.{c,h}]
indent_size = 8
indent_style = tab
trim_trailing_whitespace = true