make binary not not parse complex expressions on right side (#22078)

* binary `not` only parses simple expressions

fixes #16324

* switch to primary

tests/notnil/tparse.nim

@@ -0,0 +1,18 @@
+# issue #16324
+
+{.push experimental: "notnil".}
+
+block:
+  type Foo = ref object
+    value: int
+    
+  proc newFoo1(): Foo not nil =               # This compiles
+    return Foo(value: 1)
+    
+  proc newFoo2(): Foo not nil {.inline.} =    # This does not
+    return Foo(value: 1)
+
+  doAssert newFoo1().value == 1
+  doAssert newFoo2().value == 1
+
+{.pop.}