change hashtag formatting

crates/compiler/fmt/src/spaces.rs

@@ -154,7 +154,9 @@ fn fmt_comment(buf: &mut Buf, comment: &str) {
     }
 
     buf.push('#');
-    if !comment.starts_with(' ') {
+    // Add a space between the starting `#` and the rest of the comment,
+    // unless there already is one or the comment is of the form `#### something`.
+    if !comment.starts_with(' ') && !comment.starts_with('#') {
         buf.spaces(1);
     }
     buf.push_str(comment.trim_end());

crates/compiler/test_syntax/tests/snapshots/pass/mixed_docs.expr.formatted.roc

@@ -1,7 +0,0 @@
-# ## not docs!
-## docs, but with a problem
-## (namely that this is a mix of docs and regular comments)
-# not docs
-x = 5
-
-42

crates/compiler/test_syntax/tests/snapshots/pass/not_docs.expr.formatted.roc

@@ -1,7 +0,0 @@
-# ######
-# ## not docs!
-# #still not docs
-# #####
-x = 5
-
-42