editorconfig settings: attempt to guarantee the final end-of-line char

Author: eli-schwartz

Diff for: .editorconfig

@@ -5,6 +5,7 @@ charset = utf-8
 end_of_line = lf
 indent_style = space
 trim_trailing_whitespace = true
+insert_final_newline = true
 
 [*.[ch]]
 indent_size = 4