CLI tool built with syn v2

No new options, just updated dependencies.

Use older release for small executable files.

More options

• --pretty mode to pretty-print without using external rustfmt. Not everything is supported though.
• --full-crate-tree allows duplicating modules that point to multiple files based on cfg values, allowing to analyse all crate source code variants in one go.

Better CLI tool

• --loopify and --undoc
• CLI analogues of envvars for settings cfgs
• --output CLI option
• Better error messages

First release

"expand" example.
As it uses only minimal OS features, I expect it to work on large variety of platforms.