Improve the margin calculation for the search command's UI

Signed-off-by: hi-rustin <rustin.liu@gmail.com>

src/cargo/ops/registry/search.rs

@@ -3,7 +3,6 @@
 //! [1]: https://doc.rust-lang.org/nightly/cargo/reference/registry-web-api.html#search
 
 use std::cmp;
-use std::iter::repeat;
 
 use anyhow::Context as _;
 use url::Url;
@@ -35,7 +34,8 @@ pub fn search(
         .map(|krate| format!("{} = \"{}\"", krate.name, krate.max_version))
         .collect::<Vec<String>>();
 
-    let description_margin = names.iter().map(|s| s.len() + 4).max().unwrap_or_default();
+    let mut description_margin = names.iter().map(|s| s.len()).max().unwrap_or_default();
+    description_margin += 4;
 
     let description_length = cmp::max(80, 128 - description_margin);
 
@@ -54,10 +54,12 @@ pub fn search(
     for (name, description) in names.into_iter().zip(descriptions) {
         let line = match description {
             Some(desc) => {
-                let space = repeat(' ')
-                    .take(description_margin - name.len())
-                    .collect::<String>();
-                name + &space + "# " + &desc
+                format!(
+                    "{name: <margin$}# {desc}",
+                    name = name,
+                    margin = description_margin,
+                    desc = desc
+                )
             }
             None => name,
         };