sidekick: fix completionpopup regarding macro recorder

When the Sidekick completion popup is active but no item is selected, and the user types some text, it isn't recorded.
This is only when the option "immediate complete if possible" is disabled,
"show completion popups where possible" is enabled,
"automatic completion popup get focus" is disabled.

I see this with javasidekick and XML plugin :

in XMLPlugin (inspired by https://sourceforge.net/tracker/?func=detail&aid=857802&group_id=588&atid=565475\):
File / New
File / Save c:\temp\1.xml
Macro / Record Temporary Macro

type:
<book>bla</
at this point, the sidekick completion popup shows up, proposing "</book>". Ignore it and continue typing "book>"

Macro / Stop Recording
The macro didn't record anything past "bla<".

In JavaSidekick:
open a java file
Macro / Record Temporary Macro
place the cursor in a method
type "System."
the completion popup appears
continue typing "arraycopy(toto)"
Macro / Stop Recording

Nothing past "System" gets recorded.

With this patch, input typed by the user when the popup menu is active is recorded. Calling TextArea.userInput() doesn't suffice.