vi: add ":prev" command support

function                                             old     new   delta
colon                                               2844    2891     +47
vi_main                                              243     255     +12
text_yank                                             54      56      +2
refresh                                              780     774      -6

Signed-off-by: Dennis Groenen <tj.groenen@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
1 file changed