update keyboard shortcuts in screenshots and docs

README.md

@@ -28,7 +28,7 @@ src/teliva hanoi.tlv
 <img alt='screenshot of Teliva running the Towers of Hanoi' src='doc/hanoi.png'>
 
 No matter what app you run, you are always guaranteed access to a single
-obvious, consistent way (currently the hotkey `ctrl-e`) to inspect its
+obvious, consistent way (currently the hotkey `ctrl-u`) to inspect its
 sources.
 
 When you look under the hood of an app, the first thing you see is a
@@ -37,8 +37,8 @@ view of the app's code.
 
 <img alt='screenshot of big-picture view for the Towers of Hanoi' src='doc/hanoi-big-picture.png'>
 
-Select a definition, make a change, hit `ctrl-e` again, and the app will run
-with your updates. ([video](https://archive.org/details/akkartik-2021-11-14))
+Select a definition, make a change, hit `ctrl-x`, and the app will run with
+your updates. ([video](https://archive.org/details/akkartik-2021-11-14))
 
 You will need some Unix-like platform with a C compiler and the ncurses and
 openssl libraries. Some possible commands to install them, depending on your