added hello aider example

docs/install.md

@@ -78,7 +78,7 @@ Some things to be aware of:
 * The `ctags` command needs to be on your shell path so that it will run by default when aider invokes `ctags ...`.
 * You need a build which includes the json feature. You can check by running `ctags --version` and looking for `+json` in the `Optional compiled features` list.
 
-```bash
+```
 $ ctags --version
 
 Universal Ctags 6.0.0, Copyright (C) 2015-2022 Universal Ctags Team

examples/hello.md

@@ -0,0 +1,25 @@
+# Hello aider!
+
+Here is the simplest possible "hello world" example of using aider:
+
+<div class="chat-transcript" markdown="1">
+
+#### change hello to goodbye
+
+To change the output from "hello" to "goodbye", we need to modify the `hello.py` file.
+
+Here is the change:
+
+```python
+hello.py
+<<<<<<< ORIGINAL
+print("hello")
+=======
+print("goodbye")
+>>>>>>> UPDATED
+```
+
+> Applied edit to hello.py
+> Commit 672ae42 aider: Changed output from "hello" to "goodbye" in hello.py.
+
+</div>