Return on a blank line inserts two line breaks instead of one

[rodgco]

Pressing Return on a line that is already blank inserts two line breaks instead of one, so every press adds two blank lines rather than one.

Steps to reproduce

1. Open Omawrite with one, a blank line, then two:

   one
   
   two
   

2. Put the caret on the blank line.

3. Press Return once.

Expected

One new blank line:

one


two

Actual

Two:

one



two

Pressing Return again adds two more, so the gap grows in twos: one\n\n\n\n\n\ntwo.

It also shows up in an empty document — the first Return leaves two blank lines rather than one.

Where it comes from

smartReturn in src/Main.qml ends with a fallback for any line that is not a list item and not inside a code fence:

replaceSelectionWith("\n\n");

That is right for a paragraph: a new paragraph in this editor is separated from the one above by a blank line, so Return at the end of two correctly produces two\n\n. But on a line that is already blank there is no paragraph to separate from, and the separator becomes a second empty line nobody asked for.

The list-item and code-fence branches above it are unaffected — both insert a single \n.

Verified on

master at 8f98892, by driving a real window in the test harness with the keyboard:

Start (caret)	Key	Result
one\n\ntwo (on the blank line)	Return	one\n\n\n\ntwo ❌
one\n\ntwo (end of two)	Return	one\n\ntwo\n\n ✅
`` (empty document)	Return	\n\n ❌
one\n\ntwo (on the blank line)	Return ×2	one\n\n\n\n\n\ntwo ❌

Happy to send a PR if that is useful.