refactor doc structure

Author: jodersky

book/src/README.md

@@ -35,6 +35,16 @@ In a terminal:
 
 - Support for subcommands (aka "verbs")
 
+## Binaries
+
+This library is published for Scala 3 and 2.13, for the JVM and Native. It is
+available on maven central under the coordinates:
+
+- mill: `ivy"io.crashbox::argparse::{{#include ../../out/releaseVersion.dest/version}}"`
+
+- sbt: `"io.crashbox" %%% "argparse" % "{{#include ../../out/releaseVersion.dest/version}}"`
+
+
 ## Getting Help
 
 | Channel | Links |

book/src/SUMMARY.md

@@ -1,9 +1,8 @@
 # Summary
 
 - [Introduction](./README.md)
-- [Binaries](./binaries.md)
 - [Annotation Interface](./annotation.md)
-- [Lower-Level Interface](./ll/README.md)
+- [Argparse Interface](./ll/README.md)
   - [Tutorial](./ll/tutorial.md)
   - [Cookbook](./ll/cookbook.md)
 - [Usecases](./usecases.md)