EditorConfig: set indent_size = tab

Despite `indent_size` being set to `tab` by default, it turns out that we set `indent_size` to `2` for `*` at the top of this file. So, for everywhere else, explicitly set `indent_size` to the default (`tab`). This should achieve the goal of my last patch to `.editorconfig`.

.editorconfig

@@ -13,16 +13,18 @@ insert_final_newline = true
 trim_trailing_whitespace = false
 
 [.git*]
+indent_size = tab
 indent_style = tab
 
 [{**.*sh,test/run}]
+indent_size = tab
 indent_style = tab
 
 shell_variant      = bash
 binary_next_line   = true  # like -bn
 switch_case_indent = true  # like -ci
 space_redirects    = true  # like -sr
-keep_padding       = false  # like -kp
+keep_padding       = false # like -kp
 end_of_line        = lf
 charset            = utf-8
 trim_trailing_whitespace = true