fixes #9839; fixes noReturn pragma doesn't work for non-simple templates (#21048)

tests/controlflow/tunreachable.nim

@@ -0,0 +1,32 @@
+discard """
+  cmd: "nim check --warningAsError:UnreachableCode $file"
+  action: "reject"
+  nimout: '''
+tunreachable.nim(23, 3) Error: unreachable code after 'return' statement or '{.noReturn.}' proc [UnreachableCode]
+tunreachable.nim(30, 3) Error: unreachable code after 'return' statement or '{.noReturn.}' proc [UnreachableCode]
+'''
+"""
+  
+# bug #9839
+template myquit1():untyped=
+  ## foo
+  quit(1)
+template myquit2():untyped=
+  echo 123
+  myquit1()
+
+proc main1()=
+
+  # BUG: uncommenting this doesn't give `Error: unreachable statement`
+  myquit2()
+
+  echo "after"
+
+main1()
+
+proc main2() =
+  myquit1()
+
+  echo "after"
+
+main2()