fix: rename "Unknown option" to "unrecognized option" for diff and cmp (#179)

Author: Ryujiyasu

src/cmp.rs

@@ -217,7 +217,7 @@ pub fn parse_params<I: Iterator<Item = OsString>>(mut opts: Peekable<I>) -> Resu
             std::process::exit(0);
         }
         if param_str.starts_with('-') {
-            return Err(format!("Unknown option: {param:?}"));
+            return Err(format!("unrecognized option: {param:?}"));
         }
         if from.is_none() {
             from = Some(param);

src/params.rs

@@ -195,7 +195,7 @@ pub fn parse_params<I: Iterator<Item = OsString>>(mut opts: Peekable<I>) -> Resu
             Err(error) => return Err(error),
         }
         if param.to_string_lossy().starts_with('-') {
-            return Err(format!("Unknown option: {param:?}"));
+            return Err(format!("unrecognized option: {param:?}"));
         }
         if from.is_none() {
             from = Some(param);

tests/integration.rs

@@ -39,7 +39,9 @@ mod common {
             cmd.assert()
                 .code(predicate::eq(2))
                 .failure()
-                .stderr(predicate::str::starts_with("Unknown option: \"--foobar\""));
+                .stderr(predicate::str::starts_with(
+                    "unrecognized option: \"--foobar\"",
+                ));
         }
         Ok(())
     }