docs(README): add headings to examples

README.md

@@ -29,12 +29,16 @@ These examples are generated by [./scripts/examples.sh](scripts/examples.sh).
 Note some of these examples send automated input to an interactive bash
 session.
 
+### Cowsay
+
 ```bash
 $ termsnap -l 9 -c 28 -- cowsay Hello, world
 ```
 
 ![Termsnap output of the cowsay command saying "hello world"](./media/cow.svg)
 
+### Neovim
+
 ```bash
 $ termsnap -l 12 -c 60 -- nvim --clean ./scripts/example.py <<EOF
 :set number
@@ -45,6 +49,8 @@ EOF
 
 ![Termsnap output of example Python code viewed in Neovim](./media/nvim.svg)
 
+### ANSI colors
+
 ```bash
 $ (
     # `sleep` gives bash time to be ready for the command, if this is omitted
@@ -57,6 +63,8 @@ $ (
 
 ![Termsnap output of a dump of indexed terminal colors](./media/colors.svg)
 
+### TTY information
+
 ```bash
 $ (
     sleep 0.05
@@ -69,6 +77,8 @@ $ (
 
 ![Termsnap output of some tty commands](./media/tty.svg)
 
+### Tokei
+
 ```bash
 $ termsnap -l 22 -c 80 -- tokei
 ```