feat: set message for multiple revsets

Allows to set the revision message of multiple revisions by passing
them as arguments. This only supports simple revisions, such as `@`,
`@-`, `xs`, and so on. Comple revisions such as `@..@-` are not
supported.

Fixes: #5

src/cli/mod.rs

@@ -14,4 +14,19 @@ use clap::Parser;
                   Jujutsu repository.\n\n\
                   This tool requires an interactive terminal (TTY)."
 )]
-pub struct Cli;
+pub struct Cli {
+    /// The revision(s) whose description to edit (default: @)
+    #[arg(value_name = "REVSETS")]
+    revsets: Vec<String>,
+}
+
+impl Cli {
+    /// Returns the revsets to operate on, defaulting to `["@"]` if none provided
+    pub fn revsets(&self) -> Vec<&str> {
+        if self.revsets.is_empty() {
+            vec!["@"]
+        } else {
+            self.revsets.iter().map(|s| s.as_str()).collect()
+        }
+    }
+}