README.adoc: rewrite the pitch

I suppose it's now "shell directory navigator" rather than "simple ...".

README.adoc

@@ -2,19 +2,17 @@ sdn
 ===
 :compact-option:
 
-'sdn' is a simple directory navigator that you can invoke while editing shell
-commands.  It enables you to:
+'sdn' is a keyboard-driven file picker and directory navigator for your shell.
 
- * take a quick peek at directory contents without running `ls`;
- * select files to insert into the command line;
- * browse the filesystem without all the mess that Midnight Commander does:
-   there's no need to create a subshell in a new pty.  The current command line
-   can be simply forwarded if it is to be edited.  What's more, it will always
-   be obvious whether the navigator is running.
+Press Alt-o at any point while composing a command to explore the filesystem
+visually.  When you return, 'sdn' can change the shell's working directory,
+or insert one or more shell-quoted paths directly into the command line,
+all without discarding what you were already typing.
 
-'sdn' runs on Linux, all BSD derivatives, and within MSYS2.  I wanted to try
-a different, simpler approach with this project, and the end result is
-very friendly to tinkering.
+The high-level goal has been to turn Midnight Commander inside out: unlike with
+MC's Ctrl-o escape, it will always be obvious whether the navigator is running.
+
+'sdn' runs on Linux, all BSD derivatives, and within MSYS2.
 
 image::sdn.png[align="center"]
 
@@ -122,6 +120,11 @@ be hacked around in 'mc.ext' by turning on the `nroff` switch for a custom file
 extension, just without actually invoking 'nroff'), and thus it can't show the
 program help.  'sdn' is currently optimised for 'less' as the pager.
 
+Notes
+-----
+I wanted to try a different, simpler approach with this project, and the end
+result is very friendly to tinkering.
+
 Contributing and Support
 ------------------------
 Use https://git.janouch.name/p/sdn to report any bugs, request features,