feat: Allow bulk-adding of snippets, footers, annotations

This will make it easier for diagnostic systems to convert their
messages to a `Message`

src/snippet.rs

@@ -34,10 +34,20 @@ impl<'a> Message<'a> {
         self
     }
 
+    pub fn snippets(mut self, slice: impl IntoIterator<Item = Snippet<'a>>) -> Self {
+        self.snippets.extend(slice);
+        self
+    }
+
     pub fn footer(mut self, footer: Label<'a>) -> Self {
         self.footer.push(footer);
         self
     }
+
+    pub fn footers(mut self, footer: impl IntoIterator<Item = Label<'a>>) -> Self {
+        self.footer.extend(footer);
+        self
+    }
 }
 
 pub struct Label<'a> {
@@ -116,6 +126,11 @@ impl<'a> Snippet<'a> {
         self
     }
 
+    pub fn annotations(mut self, annotation: impl IntoIterator<Item = Annotation<'a>>) -> Self {
+        self.annotations.extend(annotation);
+        self
+    }
+
     pub fn fold(mut self, fold: bool) -> Self {
         self.fold = fold;
         self

tests/fixtures/deserialize.rs

@@ -42,12 +42,8 @@ impl<'a> From<MessageDef<'a>> for Message<'a> {
         if let Some(id) = id {
             message = message.id(id);
         }
-        message = snippets
-            .into_iter()
-            .fold(message, |message, snippet| message.snippet(snippet));
-        message = footer
-            .into_iter()
-            .fold(message, |message, label| message.footer(label));
+        message = message.snippets(snippets);
+        message = message.footers(footer);
         message
     }
 }
@@ -111,11 +107,7 @@ impl<'a> From<SnippetDef<'a>> for Snippet<'a> {
         if let Some(origin) = origin {
             snippet = snippet.origin(origin)
         }
-        snippet = annotations
-            .into_iter()
-            .fold(snippet, |snippet, annotation| {
-                snippet.annotation(annotation)
-            });
+        snippet = snippet.annotations(annotations);
         snippet
     }
 }