Allow std/macros.params to work with nnkProcTy (#19563)

* Allow std/macros.params to work with nnkProcTy

* Add tests for proc params & pragma

tests/macros/tprochelpers.nim

@@ -0,0 +1,22 @@
+import std/macros
+import stdtest/testutils
+
+macro test1(prc: untyped): untyped =
+  assertAll:
+    prc.params.len == 2
+    prc.params[1].len == 4
+    prc.pragma.len == 2
+
+  prc.params = nnkFormalParams.newTree(
+    ident("int")
+  )
+  prc.pragma = newEmptyNode()
+
+  assertAll:
+    prc.params.len == 1
+    prc.pragma.len == 0
+  prc
+
+proc test(a, b: int): int {.gcsafe, raises: [], test1.} = 5
+
+type hello = proc(a, b: int): int {.gcsafe, raises: [], test1.}