Add prefix customization command

src/framework/commands/arguments.rs

@@ -31,6 +31,10 @@ impl FromArguments for String {
     }
 }
 
+/// Consumes the entire remaining string as a single argument. If no string is remaining, it
+/// returns an empty string.
+///
+/// Parsing this argument type never fails.
 pub struct GreedyString(pub String);
 
 impl FromArguments for GreedyString {

src/framework/commands/mod.rs

@@ -20,6 +20,9 @@ pub enum CommandError {
 
     #[error("A database operation failed due to an inconsistent state")]
     DatabaseInconsistentState,
+
+    #[error("The command was used in DMs, but it can only be used in servers")]
+    ServerCommandRunInDMs,
 }
 
 #[async_trait]
@@ -66,7 +69,10 @@ pub fn get_command_parts<'a>(prefix: &str, message: &'a str) -> Option<CommandPa
         .to_ascii_lowercase()
         .starts_with(&prefix.to_ascii_lowercase())
     {
-        let message = message_trimmed_start.split_at(prefix.len()).1.trim_ascii_start();
+        let message = message_trimmed_start
+            .split_at(prefix.len())
+            .1
+            .trim_ascii_start();
 
         match message.split_once(" ") {
             Some((name, args)) => Some(CommandParts::new(name, args)),

src/framework/commands/runner.rs

@@ -32,7 +32,10 @@ impl<T: Send + Sync + 'static> OnMessageHandler<T> for CommandRunner {
 
                 if let Some(command) = command {
                     command
-                        .execute(CommandContext::new(event, rt.clone(), &prefixes[0]), parts.args)
+                        .execute(
+                            CommandContext::new(event, rt.clone(), &prefixes[0]),
+                            parts.args,
+                        )
                         .await?;
 
                     break;