lower: generalise the *T-where-T-expected diagnostic to any pointer

The check only caught `for xs: (*m)` loop captures; passing a `*T`
parameter or any pointer local where `T` is expected still slipped through
to the LLVM verifier. Key the diagnostic on the lowered argument's type
instead of the capture, so a `*Move` parameter forwarded into a by-value
parameter is reported the same way. Ref-capture wording is preserved.

Add example 216 (pointer-parameter case) alongside 215 (loop capture).

tests/expected/216-pointer-param-value-arg-diagnostic.exit

@@ -0,0 +1 @@
+1

tests/expected/216-pointer-param-value-arg-diagnostic.txt

@@ -0,0 +1,10 @@
+error: argument 'm' has type '*Move', but 'Move' is expected here
+  --> /Users/agra/projects/sx/examples/216-pointer-param-value-arg-diagnostic.sx:13:44
+   |
+13 | forward :: (m: *Move) -> s64 { return take(m); }
+   |                                            ^
+
+help: dereference it to pass the value: `m.*`
+   |
+13 | m.*
+   |                                            ^