[Docs] Convert remaining code snippets in docs (#26422)

This commit converts the last remaining code snippets so that they are
now testable.

docs/build.gradle

@@ -19,21 +19,6 @@
 
 apply plugin: 'elasticsearch.docs-test'
 
-/* List of files that have snippets that probably should be converted to
- * `// CONSOLE` and `// TESTRESPONSE` but have yet to be converted. Try and
- * only remove entries from this list. When it is empty we'll remove it
- * entirely and have a party! There will be cake and everything.... */
-buildRestTests.expectedUnconvertedCandidates = [
-  'reference/aggregations/bucket/nested-aggregation.asciidoc',
-  'reference/aggregations/bucket/range-aggregation.asciidoc',
-  'reference/aggregations/bucket/reverse-nested-aggregation.asciidoc',
-  'reference/aggregations/bucket/significantterms-aggregation.asciidoc',
-  'reference/aggregations/bucket/terms-aggregation.asciidoc',
-  'reference/aggregations/matrix/stats-aggregation.asciidoc',
-  'reference/aggregations/metrics/tophits-aggregation.asciidoc',
-  'reference/cluster/allocation-explain.asciidoc',
-]
-
 integTestCluster {
   setting 'script.max_compilations_per_minute', '1000'
   /* Enable regexes in painless so our tests don't complain about example

docs/reference/aggregations/bucket/nested-aggregation.asciidoc

@@ -8,9 +8,9 @@ price for the product. The mapping could look like:
 
 [source,js]
 --------------------------------------------------
+PUT /index
 {
-    ...
-
+  "mappings": {
     "product" : {
         "properties" : {
             "resellers" : { <1>
@@ -22,15 +22,18 @@ price for the product. The mapping could look like:
             }
         }
     }
+  }
 }
 --------------------------------------------------
-
+// CONSOLE
+// TESTSETUP
 <1> The `resellers` is an array that holds nested documents under the `product` object.
 
 The following aggregations will return the minimum price products can be purchased in:
 
 [source,js]
 --------------------------------------------------
+GET /_search
 {
     "query" : {
         "match" : { "name" : "led tv" }
@@ -47,6 +50,9 @@ The following aggregations will return the minimum price products can be purchas
     }
 }
 --------------------------------------------------
+// CONSOLE
+// TEST[s/GET \/_search/GET \/_search\?filter_path=aggregations/]
+// TEST[s/^/PUT index\/product\/0\?refresh\n{"name":"led", "resellers": [{"name": "foo", "price": 350.00}, {"name": "bar", "price": 500.00}]}\n/]
 
 As you can see above, the nested aggregation requires the `path` of the nested documents within the top level documents.
 Then one can define any type of aggregation over these nested documents.
@@ -56,12 +62,16 @@ Response:
 [source,js]
 --------------------------------------------------
 {
-    "aggregations": {
-        "resellers": {
-            "min_price": {
-                "value" : 350
-            }
-        }
+  ...
+  "aggregations": {
+    "resellers": {
+      "doc_count": 0,
+      "min_price": {
+        "value": 350
+      }
     }
+  }
 }
 --------------------------------------------------
+// TESTRESPONSE[s/\.\.\.//]
+// TESTRESPONSE[s/: [0-9]+/: $body.$_path/]