Add contains to std/macrocache (#21304)

* Add test cases

* Implement contains for CacheSeq

* Implement contains for CacheTable

* Fix implementation of hasKey

* Remove contains for CacheSeq

Fix runnable examples

I was accidently using --doccmd:skip so I didn't spot the failure locally

* Implement hasKey as a VM callback instead of magic

* Implement suggestions from PR

Co-Authored-By: ringabout <ringabout@users.noreply.github.com>

* Update lib/core/macrocache.nim

---------

Co-authored-by: ringabout <ringabout@users.noreply.github.com>
Co-authored-by: ringabout <43030857+ringabout@users.noreply.github.com>

lib/core/macrocache.nim

@@ -181,6 +181,32 @@ proc `[]`*(t: CacheTable; key: string): NimNode {.magic: "NctGet".} =
       # get the NimNode back
       assert mcTable["toAdd"].kind == nnkStmtList
 
+proc hasKey*(t: CacheTable; key: string): bool =
+  ## Returns true if `key` is in the table `t`.
+  ##
+  ## See also:
+  ## * [contains proc][contains(CacheTable, string)] for use with the `in` operator
+  runnableExamples:
+    import std/macros
+    const mcTable = CacheTable"hasKeyEx"
+    static:
+      assert not mcTable.hasKey("foo")
+      mcTable["foo"] = newEmptyNode()
+      # Will now be true since we inserted a value
+      assert mcTable.hasKey("foo")
+  discard "Implemented in vmops"
+
+proc contains*(t: CacheTable; key: string): bool {.inline.} =
+  ## Alias of [hasKey][hasKey(CacheTable, string)] for use with the `in` operator.
+  runnableExamples:
+    import std/macros
+    const mcTable = CacheTable"containsEx"
+    static:
+      mcTable["foo"] = newEmptyNode()
+      # Will be true since we gave it a value before
+      assert "foo" in mcTable
+  t.hasKey(key)
+
 proc hasNext(t: CacheTable; iter: int): bool {.magic: "NctHasNext".}
 proc next(t: CacheTable; iter: int): (string, NimNode, int) {.magic: "NctNext".}