keep param pragmas in typed proc AST (#24711)

fixes #24702

(cherry picked from commit 1f8da3835f)

tests/pragmas/tparamcustompragma.nim

@@ -0,0 +1,16 @@
+discard """
+  nimout: '''
+proc foo(a {.attr.}: int) =
+  discard
+
+'''
+"""
+
+# fixes #24702
+
+import macros
+template attr*() {.pragma.}
+proc foo(a {.attr.}: int) = discard
+macro showImpl(a: typed) =
+  echo repr getImpl(a)
+showImpl(foo)