add editorconfig

Author: SingingBush

.editorconfig

@@ -0,0 +1,17 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+
+[*.{c,h,d,di,dd,json}]
+insert_final_newline = true
+indent_style = space
+indent_size = 4
+trim_trailing_whitespace = true
+
+[*.{yml}]
+indent_size = 2
+
+[*.md]
+trim_trailing_whitespace = false