Fix behaviour of the left and right keys after SCI_SETSELECTIONMODE(SC_SEL_STREAM) where moving both left and right collapsed the selection instead of shrinking the selection by one character.
Fix behaviour of the left and right keys after SCI_SETSELECTIONMODE(SC_SEL_STREAM)
where moving both left and right collapsed the selection instead of shrinking the
selection by one character.

windoze/scintilla,windoze/scintilla,windoze/scintilla,windoze/scintilla,windoze/scintilla,windoze/scintilla,windoze/scintilla,windoze/scintilla