[fractal] Implement Display instead of ToString trait

[Marge Bot <marge-bot src gnome org>]

commit 341c1258187478acac94528b72dbd3616d539e7e
Author: Julian Sparber <julian sparber net>
Date:   Wed Apr 27 14:38:22 2022 +0200

    Implement Display instead of ToString trait
    
    Part-of: <https://gitlab.gnome.org/GNOME/fractal/-/merge_requests/1086>

 src/session/room/room_type.rs        |  8 ++++----
 src/session/sidebar/category_type.rs | 11 +++++++----
 src/session/sidebar/entry_type.rs    | 12 ++++++++----
 3 files changed, 19 insertions(+), 12 deletions(-)
---
diff --git a/src/session/room/room_type.rs b/src/session/room/room_type.rs
index 1dc3ab9b3..1cbe46776 100644
--- a/src/session/room/room_type.rs
+++ b/src/session/room/room_type.rs
@@ -1,4 +1,4 @@
-use std::convert::TryFrom;
+use std::{convert::TryFrom, fmt};
 
 use gtk::glib;
 use num_enum::{IntoPrimitive, TryFromPrimitive};
@@ -73,9 +73,9 @@ impl Default for RoomType {
     }
 }
 
-impl ToString for RoomType {
-    fn to_string(&self) -> String {
-        CategoryType::from(self).to_string()
+impl fmt::Display for RoomType {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        CategoryType::from(self).fmt(f)
     }
 }
 
diff --git a/src/session/sidebar/category_type.rs b/src/session/sidebar/category_type.rs
index c31ce3ff9..ae1a72dcd 100644
--- a/src/session/sidebar/category_type.rs
+++ b/src/session/sidebar/category_type.rs
@@ -1,3 +1,5 @@
+use std::fmt;
+
 use gettextrs::gettext;
 use gtk::glib;
 
@@ -25,9 +27,9 @@ impl Default for CategoryType {
     }
 }
 
-impl ToString for CategoryType {
-    fn to_string(&self) -> String {
-        match self {
+impl fmt::Display for CategoryType {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let label = match self {
             CategoryType::None => unimplemented!(),
             CategoryType::VerificationRequest => gettext("Verifications"),
             CategoryType::Invited => gettext("Invited"),
@@ -39,7 +41,8 @@ impl ToString for CategoryType {
             CategoryType::Outdated => gettext("Outdated"),
             CategoryType::Space => gettext("Spaces"),
             CategoryType::Direct => gettext("People"),
-        }
+        };
+        f.write_str(&label)
     }
 }
 
diff --git a/src/session/sidebar/entry_type.rs b/src/session/sidebar/entry_type.rs
index 366739375..fa67bb04d 100644
--- a/src/session/sidebar/entry_type.rs
+++ b/src/session/sidebar/entry_type.rs
@@ -1,3 +1,5 @@
+use std::fmt;
+
 use gettextrs::gettext;
 use gtk::glib;
 
@@ -15,11 +17,13 @@ impl Default for EntryType {
     }
 }
 
-impl ToString for EntryType {
-    fn to_string(&self) -> String {
-        match self {
+impl fmt::Display for EntryType {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let label = match self {
             EntryType::Explore => gettext("Explore"),
             EntryType::Forget => gettext("Forget Room"),
-        }
+        };
+
+        f.write_str(&label)
     }
 }