Add autocomplete to link fields / bard editor link URL select.

[replete]

Currently adding a link to an existing page is:

• Select text
• click Link icon in editor
• click URL dropdown in popup
• click 'Entry' in popup
• click 'Browse' in popup
• search for page in page browser
• tick box
• click save in popup

What I'd love to see is:

• select text
• click Link icon in editor
• click 'Entry' button in a buttongroup (no select dropdown)
• start typing to find page
• choose to save