Fix behavior of 'deselect-all' to only deselect matches

To make it consistent with select-all and toggle-all.

Close #1364

src/terminal.go

@@ -1837,8 +1837,12 @@ func (t *Terminal) Loop() {
 				}
 			case actDeselectAll:
 				if t.multi > 0 {
-					t.selected = make(map[int32]selectedItem)
-					t.version++
+					for i := 0; i < t.merger.Length() && len(t.selected) > 0; i++ {
+						item := t.merger.Get(i).item
+						if _, found := t.selected[item.Index()]; found {
+							t.deselectItem(item)
+						}
+					}
 					req(reqList, reqInfo)
 				}
 			case actToggle:

test/test_go.rb

@@ -865,16 +865,22 @@ class TestGoFZF < TestBase
     tmux.until { |lines| lines[-2].include? '(100)' }
     tmux.send_keys :Tab, :Tab
     tmux.until { |lines| lines[-2].include? '(98)' }
+    tmux.send_keys '100'
+    tmux.until { |lines| lines.match_count == 1 }
+    tmux.send_keys 'C-d'
+    tmux.until { |lines| lines[-2].include? '(97)' }
+    tmux.send_keys 'C-u'
+    tmux.until { |lines| lines.match_count == 100 }
     tmux.send_keys 'C-d'
     tmux.until { |lines| !lines[-2].include? '(' }
-    tmux.send_keys :Tab, :Tab
+    tmux.send_keys :BTab, :BTab
     tmux.until { |lines| lines[-2].include? '(2)' }
     tmux.send_keys 0
     tmux.until { |lines| lines[-2].include? '10/100' }
     tmux.send_keys 'C-a'
     tmux.until { |lines| lines[-2].include? '(12)' }
     tmux.send_keys :Enter
-    assert_equal %w[2 1 10 20 30 40 50 60 70 80 90 100],
+    assert_equal %w[1 2 10 20 30 40 50 60 70 80 90 100],
                  readonce.split($INPUT_RECORD_SEPARATOR)
   end