Use strings instead of integer ids for simulate examples (#5061)

* Use strings instead of integer ids for simulate examples

These examples were being rendered with the `_id` as an integer, however, that is invalid and we only allow strings for integers.

* Change " -> ' because... reasons?

Author: dakrone

specification/simulate/ingest/examples/request/SimulateIngestRequestExample1.yaml

@@ -7,11 +7,11 @@ description:
 # type: request
 value:
   docs:
-    - _id: 123
+    - _id: '123'
       _index: my-index
       _source:
         foo: bar
-    - _id: 456
+    - _id: '456'
       _index: my-index
       _source:
         foo: rab

specification/simulate/ingest/examples/request/SimulateIngestRequestExample2.yaml

@@ -9,11 +9,11 @@ description:
 value:
   docs:
     - _index: my-index
-      _id: 123
+      _id: '123'
       _source:
         foo: bar
     - _index: my-index
-      _id: 456
+      _id: '456'
       _source:
         foo: rab
   pipeline_substitutions: