Use four spaces as default (Python default, as suggested by Henrik).

Range r10550-r10553 ready for merge.
 - Legacy-Id: 10553

Author: larseggert

.editorconfig

@@ -8,8 +8,8 @@ root = true
 
 [*]
 indent_style = space
-indent_size = 2
+indent_size = 4
 end_of_line = lf
 charset = utf-8
-trim_trailing_whitespace = false
+trim_trailing_whitespace = true
 insert_final_newline = true