Use a Cow<'static, str> for the Info component title

Some uses of the component (like for register) provide a static title.
We can trivially avoid the title allocation in those cases.

helix-term/src/keymap.rs

@@ -106,7 +106,7 @@ impl KeyTrieNode {
                 (events.join(", "), desc)
             })
             .collect();
-        Info::new(&self.name, &body)
+        Info::new(self.name.clone(), &body)
     }
 }
 

helix-term/src/ui/info.rs

@@ -24,7 +24,7 @@ impl Component for Info {
         surface.clear_with(area, popup_style);
 
         let block = Block::bordered()
-            .title(self.title.as_str())
+            .title(self.title.as_ref())
             .border_style(popup_style);
 
         let margin = Margin::horizontal(1);

helix-view/src/info.rs

@@ -1,12 +1,12 @@
 use crate::register::Registers;
 use helix_core::unicode::width::UnicodeWidthStr;
-use std::fmt::Write;
+use std::{borrow::Cow, fmt::Write};
 
 #[derive(Debug)]
 /// Info box used in editor. Rendering logic will be in other crate.
 pub struct Info {
     /// Title shown at top.
-    pub title: String,
+    pub title: Cow<'static, str>,
     /// Text body, should contain newlines.
     pub text: String,
     /// Body width.
@@ -16,17 +16,19 @@ pub struct Info {
 }
 
 impl Info {
-    pub fn new<T, U>(title: &str, body: &[(T, U)]) -> Self
+    pub fn new<T, K, V>(title: T, body: &[(K, V)]) -> Self
     where
-        T: AsRef<str>,
-        U: AsRef<str>,
+        T: Into<Cow<'static, str>>,
+        K: AsRef<str>,
+        V: AsRef<str>,
     {
+        let title = title.into();
         if body.is_empty() {
             return Self {
-                title: title.to_string(),
                 height: 1,
                 width: title.len() as u16,
                 text: "".to_string(),
+                title,
             };
         }
 
@@ -48,7 +50,7 @@ impl Info {
         }
 
         Self {
-            title: title.to_string(),
+            title,
             width: text.lines().map(|l| l.width()).max().unwrap() as u16,
             height: body.len() as u16,
             text,