Add Err in reserved keywords

Author: lucic71

cpp2rust/converter/converter_lib.cpp

@@ -73,6 +73,7 @@ static const char rust_keywords[][12] = {
     "safe",
     // Standard library keywords
     "vec",
+    "Err",
 };
 
 namespace cpp2rust {

tests/unit/keywords.cpp

@@ -1,7 +1,11 @@
 #include <cassert>
 
+int report(int Err) { return Err + 1; }
+
 int main() {
   int in = 123;
   assert(in == 123);
+  int Err = 1;
+  assert(report(Err) == 2);
   return 0;
 }