Align GUI history scroll buttons

Author: mikera

convex-gui/src/main/java/convex/gui/repl/REPLPanel.java

@@ -190,7 +190,7 @@ public REPLPanel(Convex convex) {
 		inputPanel.add(inputScrollPane,"dock center");
 
 		JPanel historyPanel=new JPanel();
-		historyPanel.setLayout(new MigLayout("wrap 1"));
+		historyPanel.setLayout(new MigLayout("wrap 1,aligny center"));
 		historyPanel.add(ActionButton.build(0xe316, e->scrollHistory(-1),"Previous command in history"));
 		historyPanel.add(ActionButton.build(0xe313, e->scrollHistory(1),"Next command in history"));
 		inputPanel.add(historyPanel,"dock east");