editorconfig: add initial config file

It's a simple format handled by practically every supported platform or program
out there.

Add an initial configuration file, so we reduce the style variation of the files
in-tree.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>

.editorconfig

@@ -0,0 +1,21 @@
+# To use this config on you editor, follow the instructions at:
+# http://editorconfig.org
+
+root = true
+
+[*]
+charset = utf-8
+insert_final_newline = true
+tab_width = 8
+max_line_length = 90
+
+[Makefile]
+indent_style = tab
+
+[*.{sh,py}]
+indent_style = space
+indent_size = 4
+
+[*.{yml,yaml}]
+indent_style = space
+indent_size = 2

check_whence.py

@@ -74,6 +74,7 @@ def main():
     known_files = set(name for name in whence_list if not name.endswith("/")) | set(
         [
             ".codespell.cfg",
+            ".editorconfig",
             ".gitignore",
             ".gitlab-ci.yml",
             ".pre-commit-config.yaml",