Fixed limitation of number of fields for derived Forms.

Author: horned-sphere

api/swimos_form/examples/expand.rs

@@ -0,0 +1 @@
+fn main() {}

api/swimos_form/examples/moo.rs

@@ -0,0 +1,13 @@
+use swimos_form::Form;
+
+fn main() {
+    let _ = Moo::default();
+}
+
+#[derive(Form, Default)]
+struct Moo {
+    #[form(header_body)]
+    n: i32,
+    #[form(header)]
+    name: String,
+}

api/swimos_form/tests/structure.rs

@@ -595,6 +595,38 @@ fn generic_duplicated_bound_2() {
     let _ = s.as_value();
 }
 
+#[test]
+fn many_fields() {
+    #[derive(Form, Default)]
+
+    struct Many {
+        field1: u64,
+        field2: u64,
+        field3: u64,
+        field4: u64,
+        field5: u64,
+        field6: u64,
+        field7: u64,
+        field8: u64,
+        field9: u64,
+        field10: u64,
+        field11: u64,
+        field12: u64,
+        field13: u64,
+        field14: u64,
+        field15: u64,
+        field16: u64,
+        field17: u64,
+        field18: u64,
+        field19: u64,
+        field20: u64,
+    }
+
+    let s = Many::default();
+
+    let _ = s.as_value();
+}
+
 #[test]
 fn test_newtype() {
     {