Mark `macros.error` as `.noreturn.` (#23081)

Closes #14329 

Marks `macros.error` as `.noreturn` so that it can be used in
expressions. This also fixes the issue that occurred in #19659 where a
stmt that could be an expression (Due to having `discardable` procs at
the end of other branches) would believe a `noreturn` proc is returning
the same type e.g.
```nim
 proc bar(): int {.discardable.} = discard

if true: bar()
else: quit(0) # Says that quit is of type `int` and needs to be used/discarded except it actually has no return type
```

1 files changed, 4 insertions, 0 deletions

diff --git a/tests/macros/t14329.nim b/tests/macros/t14329.nim
new file mode 100644
index 000000000..b5606424a
--- /dev/null
+++ b/tests/macros/t14329.nim
@@ -0,0 +1,4 @@
+import macros
+
+macro myMacro(n) =
+  let x = if true: newLit"test" else: error "error", n