hc-generate: Change default template to rust-proc and improve documentation

CHANGELOG-UNRELEASED.md

@@ -8,6 +8,8 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ### Changed
 
+- Changed `hc generate` to use the `rust-proc` template by default [PR#2009](https://github.com/holochain/holochain-rust/pull/2009)
+
 ### Deprecated
 
 ### Removed

crates/cli/src/main.rs

@@ -61,8 +61,11 @@ enum Cli {
         #[structopt(parse(from_os_str))]
         /// The path to the zome that should be generated (usually in ./zomes/)
         zome: PathBuf,
-        #[structopt(default_value = "rust")]
-        /// Either the name of a built-in template (rust, rust-proc) or the url to a git repo containing a Zome template.
+        #[structopt(default_value = "rust-proc")]
+        /// The template from which to generate the zome
+        ///
+        /// This should either be the name of a built-in template (rust-proc, rust) or
+        /// the url to a `tar.gz` containing a Zome template.
         template: String,
     },
     #[structopt(alias = "r")]