Fix strange behaviour when the prefix has spaces (#215)

src/framework/standard/command.rs

@@ -203,20 +203,16 @@ fn find_mention_end(content: &str, conf: &Configuration) -> Option<usize> {
 
 // Finds the end of the first continuous block of whitespace after the prefix
 fn find_end_of_prefix_with_whitespace(content: &str, position: usize) -> Option<usize> {
-    let mut ws_split = content.split_whitespace();
-    if let Some(cmd) = ws_split.nth(1) {
-        if let Some(index_of_cmd) = content.find(cmd) {
-            if index_of_cmd > position && index_of_cmd <= content.len() {
-                let slice = unsafe { content.slice_unchecked(position, index_of_cmd) }.as_bytes();
-                for byte in slice.iter() {
-                    // 0x20 is ASCII for space
-                    if *byte != 0x20u8 {
-                        return None;
-                    }
-                }
-                return Some(index_of_cmd);
-            }
+    let content_len = content.len();
+    if position >= content_len { return None; }
+
+    let slice = unsafe { content.slice_unchecked(position, content_len) }.as_bytes();
+    for i in 0..slice.len() {
+        match slice[i] {
+            // \t \n \r [space]
+            0x09 | 0x0a | 0x0d | 0x20 => {}
+            _ => return if i == 0 { None } else { Some(position + i) }
         }
     }
-    None
+    Some(content.len())
 }