fix(varcon)!: Make cluster header required

crates/varcon-core/src/borrowed.rs

@@ -1,6 +1,6 @@
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
 pub struct Cluster {
-    pub header: Option<&'static str>,
+    pub header: &'static str,
     pub entries: &'static [Entry],
     pub notes: &'static [&'static str],
 }
@@ -8,7 +8,7 @@ pub struct Cluster {
 impl Cluster {
     pub fn into_owned(self) -> crate::Cluster {
         crate::Cluster {
-            header: self.header.map(|s| s.to_owned()),
+            header: self.header.to_owned(),
             entries: self.entries.iter().map(|s| s.into_owned()).collect(),
             notes: self.notes.iter().map(|s| (*s).to_owned()).collect(),
         }

crates/varcon-core/src/lib.rs

@@ -12,7 +12,7 @@ pub use crate::parser::ClusterIter;
 
 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
 pub struct Cluster {
-    pub header: Option<String>,
+    pub header: String,
     pub entries: Vec<Entry>,
     pub notes: Vec<String>,
 }

crates/varcon-core/src/parser.rs

@@ -54,9 +54,7 @@ A Cv: acknowledgment's / Av B C: acknowledgement's
             str![[r#"
 [
     Cluster {
-        header: Some(
-            "acknowledgment <verified> (level 35)",
-        ),
+        header: "acknowledgment <verified> (level 35)",
         entries: [
             Entry {
                 variants: [
@@ -231,9 +229,7 @@ A Cv: acknowledgment's / Av B C: acknowledgement's
             str![[r#"
 [
     Cluster {
-        header: Some(
-            "acknowledgment <verified> (level 35)",
-        ),
+        header: "acknowledgment <verified> (level 35)",
         entries: [
             Entry {
                 variants: [
@@ -383,9 +379,7 @@ A Cv: acknowledgment's / Av B C: acknowledgement's
         notes: [],
     },
     Cluster {
-        header: Some(
-            "acknowledgment <verified> (level 35)",
-        ),
+        header: "acknowledgment <verified> (level 35)",
         entries: [
             Entry {
                 variants: [
@@ -559,7 +553,7 @@ impl Cluster {
                 terminated(winnow::ascii::till_line_ending, winnow::ascii::line_ending),
             );
             let mut cluster = (
-                opt(header),
+                header,
                 winnow::combinator::repeat(
                     1..,
                     terminated(Entry::parse_, winnow::ascii::line_ending),
@@ -568,7 +562,7 @@ impl Cluster {
             );
             let (header, entries, notes): (_, _, Vec<_>) = cluster.parse_next(input)?;
 
-            let header = header.map(|s| s.2.to_owned());
+            let header = header.2.to_owned();
             let notes = notes.into_iter().map(|s| s.to_owned()).collect();
             let c = Self {
                 header,
@@ -612,9 +606,7 @@ A Cv: acknowledgment's / Av B C: acknowledgement's
             actual.to_debug(),
             str![[r#"
 Cluster {
-    header: Some(
-        "acknowledgment <verified> (level 35)",
-    ),
+    header: "acknowledgment <verified> (level 35)",
     entries: [
         Entry {
             variants: [
@@ -793,9 +785,7 @@ A B C: coloration's / B. Cv: colouration's
             actual.to_debug(),
             str![[r#"
 Cluster {
-    header: Some(
-        "coloration <verified> (level 50)",
-    ),
+    header: "coloration <verified> (level 50)",
     entries: [
         Entry {
             variants: [