Correct spelling (#4152)

crates/nu-parser/src/flag.rs

@@ -132,7 +132,7 @@ mod tests {
 
         match spec {
             NamedType::Optional(_, _) => {}
-            _ => panic!("optional flag didn't parse succesfully"),
+            _ => panic!("optional flag didn't parse successfully"),
         }
     }
 }

crates/nu-parser/src/parse.rs

@@ -901,7 +901,7 @@ fn parse_arg(
         return parse_dollar_expr(lite_arg, scope);
     }
 
-    // before anything else, try to see if this is a number in paranthesis
+    // before anything else, try to see if this is a number in parenthesis
     if lite_arg.item.starts_with('(') {
         return parse_full_column_path(lite_arg, scope);
     }