added eq_token() method to LetStmt

crates/ra_syntax/src/ast/extensions.rs

@@ -234,6 +234,13 @@ impl ast::LetStmt {
             Some(node) => node.kind() == T![;],
         }
     }
+
+    pub fn eq_token(&self) -> Option<SyntaxToken> {
+        self.syntax()
+            .descendants_with_tokens()
+            .find(|t| t.kind() == EQ)
+            .and_then(|it| it.into_token())
+    }
 }
 
 impl ast::ExprStmt {