Type Annotations

- Add type annotations: [type] statement
- Add type definitions: [[name] type], [[name] := statement]
- Add type annotations example (08)
- add Quickstart.md, reference it from README

mers_lib/src/data/mod.rs

@@ -374,16 +374,16 @@ impl Display for Type {
         if self.types.is_empty() {
             write!(f, "<unreachable>")
         } else {
-            if self.types.len() > 1 {
-                write!(f, "{{")?;
-            }
+            // if self.types.len() > 1 {
+            //     write!(f, "{{")?;
+            // }
             write!(f, "{}", self.types[0])?;
             for t in self.types.iter().skip(1) {
                 write!(f, "/{t}")?;
             }
-            if self.types.len() > 1 {
-                write!(f, "}}")?;
-            }
+            // if self.types.len() > 1 {
+            //     write!(f, "}}")?;
+            // }
             Ok(())
         }
     }

mers_lib/src/data/reference.rs

@@ -74,6 +74,10 @@ impl Display for Reference {
 }
 impl Display for ReferenceT {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "&{}", self.0)
+        if self.0.types.len() > 1 {
+            write!(f, "&{{{}}}", self.0)
+        } else {
+            write!(f, "&{}", self.0)
+        }
     }
 }