add support for more keypad keys

The keypad Enter key was already supported. On some keyboard layouts like my
laptop the page-up and page-down key is more comfortable to use.
This adds a few lines but no complexity.

dmenu.c

@@ -360,9 +360,11 @@ keypress(XKeyEvent *ev)
 			                  utf8, utf8, win, CurrentTime);
 			return;
 		case XK_Left:
+		case XK_KP_Left:
 			movewordedge(-1);
 			goto draw;
 		case XK_Right:
+		case XK_KP_Right:
 			movewordedge(+1);
 			goto draw;
 		case XK_Return:
@@ -400,6 +402,7 @@ insert:
 			insert(buf, len);
 		break;
 	case XK_Delete:
+	case XK_KP_Delete:
 		if (text[cursor] == '\0')
 			return;
 		cursor = nextrune(+1);
@@ -410,6 +413,7 @@ insert:
 		insert(NULL, nextrune(-1) - cursor);
 		break;
 	case XK_End:
+	case XK_KP_End:
 		if (text[cursor] != '\0') {
 			cursor = strlen(text);
 			break;
@@ -429,6 +433,7 @@ insert:
 		cleanup();
 		exit(1);
 	case XK_Home:
+	case XK_KP_Home:
 		if (sel == matches) {
 			cursor = 0;
 			break;
@@ -437,6 +442,7 @@ insert:
 		calcoffsets();
 		break;
 	case XK_Left:
+	case XK_KP_Left:
 		if (cursor > 0 && (!sel || !sel->left || lines > 0)) {
 			cursor = nextrune(-1);
 			break;
@@ -445,18 +451,21 @@ insert:
 			return;
 		/* fallthrough */
 	case XK_Up:
+	case XK_KP_Up:
 		if (sel && sel->left && (sel = sel->left)->right == curr) {
 			curr = prev;
 			calcoffsets();
 		}
 		break;
 	case XK_Next:
+	case XK_KP_Next:
 		if (!next)
 			return;
 		sel = curr = next;
 		calcoffsets();
 		break;
 	case XK_Prior:
+	case XK_KP_Prior:
 		if (!prev)
 			return;
 		sel = curr = prev;
@@ -473,6 +482,7 @@ insert:
 			sel->out = 1;
 		break;
 	case XK_Right:
+	case XK_KP_Right:
 		if (text[cursor] != '\0') {
 			cursor = nextrune(+1);
 			break;
@@ -481,6 +491,7 @@ insert:
 			return;
 		/* fallthrough */
 	case XK_Down:
+	case XK_KP_Down:
 		if (sel && sel->right && (sel = sel->right) == next) {
 			curr = next;
 			calcoffsets();