editorconfig: Indent markdown with tabs

Since I now use Logseq for personal knowledge management, it's easier to
make all markdown files use tabs by default.

editorconfig/.editorconfig

@@ -9,6 +9,10 @@ indent_size = 2
 indent_style = space
 trim_trailing_whitespace = true
 
+# Use tab indentation for Logseq
+[*.md]
+indent_style = tab
+
 # Use tab indentation (with size 4) for the following files
 [Makefile]
 indent_style = tab