Add examples of find() to no-array-index-key docs

I missed examples of this in my first pass at this documentation.

Author: lencioni

docs/rules/no-array-index-key.md

@@ -35,6 +35,10 @@ things.every((thing, index) => {
   otherThings.push(<Hello key={index} />);
 });
 
+things.find((thing, index) => {
+  otherThings.push(<Hello key={index} />);
+});
+
 things.findIndex((thing, index) => {
   otherThings.push(<Hello key={index} />);
 });
@@ -75,6 +79,10 @@ things.every((thing) => {
   otherThings.push(<Hello key={thing.id} />);
 });
 
+things.find((thing) => {
+  otherThings.push(<Hello key={thing.id} />);
+});
+
 things.findIndex((thing) => {
   otherThings.push(<Hello key={thing.id} />);
 });