Rust: Add unresolved macro calls count as well.

Author: geoffw0

rust/ql/src/queries/summary/SummaryStats.ql

@@ -41,4 +41,6 @@ where
   key = "Macro calls - total" and value = count(MacroCall mc)
   or
   key = "Macro calls - resolved" and value = count(MacroCall mc | mc.hasExpanded())
+  or
+  key = "Macro calls - unresolved" and value = count(MacroCall mc | not mc.hasExpanded())
 select key, value order by key

rust/ql/test/query-tests/diagnostics/SummaryStats.expected

@@ -12,3 +12,4 @@
 | Lines of user code extracted | 60 |
 | Macro calls - resolved | 8 |
 | Macro calls - total | 9 |
+| Macro calls - unresolved | 1 |