Add JumpToMatchingBrace action

This commit adds the JumpToMatchingBrace action which lets the cursor
jump to a matching brace if it is on one.

Closes #853

cmd/micro/cellview.go

@@ -150,7 +150,6 @@ func (c *CellView) Draw(buf *Buffer, top, height, left, width int) {
 			if viewCol >= 0 {
 				st := curStyle
 				if colN == matchingBrace.X && lineN == matchingBrace.Y {
-					messenger.Message(matchingBrace)
 					st = curStyle.Reverse(true)
 				}
 				c.lines[viewLine][viewCol] = &Char{Loc{viewCol, viewLine}, Loc{colN, lineN}, char, char, st, 1}