GPasteHistory: split selected signal emission

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
GPasteHistory: emit selected when activating

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
Merge branch '3.0'

* 3.0:
  GPasteHistory: emit selected when activating
  GPasteHistory: split selected signal emission