Improve manual message dialog, improve message bar design

Cargo.lock

@@ -1658,6 +1658,7 @@ dependencies = [
  "relm4-macros",
  "serde",
  "serde_json",
+ "sourceview5",
  "tracing",
  "tracing-subscriber",
  "ureq",
@@ -2397,6 +2398,41 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "sourceview5"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "88c5f976a113e947bc5ec67758b2960c0db4ca76f80fb410d7cd86cd456d9ee5"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "gdk-pixbuf",
+ "gdk4",
+ "gio",
+ "glib",
+ "gtk4",
+ "libc",
+ "pango",
+ "sourceview5-sys",
+]
+
+[[package]]
+name = "sourceview5-sys"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "29637cccd56075a37ba72c0cc8b8d599dbc1d857e30dadea97eaacbc29b7fd46"
+dependencies = [
+ "gdk-pixbuf-sys",
+ "gdk4-sys",
+ "gio-sys",
+ "glib-sys",
+ "gobject-sys",
+ "gtk4-sys",
+ "libc",
+ "pango-sys",
+ "system-deps",
+]
+
 [[package]]
 name = "spin"
 version = "0.5.2"