Fixing resize split can cause crashes when node is root

Fixing resize split can cause crashes when node is root.

"Regression" of micro-editor#3983 where ResizeSplit() assumed that the root node
always has a single child which aligns to the previous behavior

Author: Neko-Box-Coder

internal/views/splits.go

@@ -186,7 +186,7 @@ func (n *Node) hResizeSplit(i int, size int) bool {
 // ResizeSplit resizes a certain split to a given size
 func (n *Node) ResizeSplit(size int) bool {
 	// TODO: `size < 0` does not work for some reason
-	if size <= 0 {
+	if size <= 0 || n.parent == nil {
 		return false
 	}
 	if len(n.parent.children) <= 1 {
@@ -542,6 +542,10 @@ func (n *Node) flatten() {
 
 // String returns the string form of the node and all children (used for debugging)
 func (n *Node) String() string {
+	if n == nil {
+		return "Root"
+	}
+
 	var strf func(n *Node, ident int) string
 	strf = func(n *Node, ident int) string {
 		marker := ""