Model: a macro name with control characters is refused on every path

Only parse_macro refused a name holding a line break or other control
character. Macros that came from the macros field of a JSON workbook
were checked with check_limits alone, so a file could bring in a macro
named "a\nb" that macro.save and macro.rename would refuse. The check
now lives in Macro::check_limits, so every path applies it, and such a
macro is dropped with the usual warning when the file is opened.

crates/engine/src/macros/mod.rs

@@ -30,9 +30,6 @@ pub fn parse_macro(v: &Json) -> Result<Macro, String> {
     let mut m: Macro = serde_json::from_value(v).map_err(|e| format!("This isn't a valid macro: {e}"))?;
     m.name = m.name.trim().to_string();
     m.check_limits()?;
-    if m.name.chars().any(char::is_control) {
-        return Err("A macro name can't hold line breaks or other control characters.".into());
-    }
     check_size(&m)?;
     Ok(m)
 }

crates/engine/src/macros/tests.rs

@@ -193,3 +193,16 @@ fn names() {
     assert_eq!(find(&wb, " MACRO1 "), Some(0));
     assert_eq!(find(&wb, "Macro2"), None);
 }
+
+#[test]
+fn json_field_macros_get_the_name_check_too() {
+    // A JSON workbook can't bring in a name that macro.save and macro.rename refuse.
+    let mut wb = Workbook::new();
+    wb.macros.push(Macro { name: "a\nb".into(), ..Macro::default() });
+    wb.macros.push(Macro { name: "Fine".into(), ..Macro::default() });
+    let bytes = crate::io::save_bytes(&wb, "ctl.json").unwrap();
+    let (back, warnings) = crate::io::open_bytes("ctl.json", &bytes).unwrap();
+    let names: Vec<&str> = back.macros.iter().map(|m| m.name.as_str()).collect();
+    assert_eq!(names, ["Fine"]);
+    assert!(warnings.len() == 1 && warnings[0].starts_with("1 macro "), "{warnings:?}");
+}