editorconfig: update to align with reality

Set the root = true flag, so tools don't continue traversing the tree
looking for more editorconfig files.

In practise we have Unix line endings so adjust the end_of_line flag and
enable UTF-8 charset.

Enable final newline for all files but patches - most editors already
insert one and git gets unhappy otherwise.

Finally, use 4 space indent for shell scripts... In practise their style
varies _a lot_ but this seems reasonable default IMHO.

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

.editorconfig

@@ -1,5 +1,15 @@
-[*.{yaml,sh,gn_args}]
-tab_width = 2
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
 indent_size = 2
-end_of_line = crlf
-indent_style = space
+indent_style = space
+insert_final_newline = true
+
+[*.sh]
+indent_size = 4
+indent_style = space
+
+[*.patch]
+insert_final_newline = false