tiptap: Hash character with the suggestion utility conflicts with heading Markdown shortcut

What’s the bug you are facing?

When using the # as the char in the Suggestion utility, this conflicts with the heading Markdown shortcut IF it’s the first character in an empty paragraph. Instead of adding the selected suggestion, the paragraph is converted to a heading instead.

How can we reproduce the bug on our side?

• Take the CodeSandbox as an example
• Type # into the editor as the first character in an empty paragraph
• Press <kbd>Enter</kbd> to select an item from the dropdown
• Observe that the empty paragraph is converted into a heading

Can you provide a CodeSandbox?

• https://codesandbox.io/s/tiptap-issue-2570-56ec10

What did you expect to happen?

The selected suggestion from the dropdown should’ve been added to the editor.

Anything to add? (optional)

A few observations:

• I understand that I can disable the heading input rule to work around this issue, but we’re looking for a way to have both things working.
• After some research I’ve noticed that all input rules take priority over anything else (i.e. the input rules handleKeyDown will take precedence over other extensions/plugins handleKeyDown event handlers, that’s why we have the behavior here described.
• Possible solution: We need a way to sort ProseMirror plugins based on a priority property (similar to what we have for extensions) so that we can have certain plugins being handled before the input rules plugin.

Did you update your dependencies?

• Yes, I’ve updated my dependencies to use the latest version of all packages.

Are you sponsoring us?

• Yes, I’m a sponsor. 💖 (on behalf of Doist)