Switching the mermaid diagram to edit mode using a keyboard only.

#11060 introduced an explicit edit mode for Mermaid diagrams. This change makes editing more inconvenient, because it now requires moving the mouse and clicking to edit a Mermaid diagram in the document. Before this feature, moving the keyboard cursor into a Mermaid diagram automatically switched the diagram into edit mode, allowing users to edit seamlessly. For example, given the following document: pre paragraph Mermaid diagram [keyboard cursor] post paragraph Pressing the Arrow Up key moved the cursor into the Mermaid diagram and expanded it into edit mode, so I could modify the diagram without using the mouse. In the recent version, however, the diagram stays in preview mode. Even though the UI looks read-only, the keyboard cursor is actually inside the diagram content—so typing changes the diagram. It’s undesirable because you can’t predict what the keyboard input will do. I think one of the following options could improve this behavior. In the same example…