Docs: CONSOLEify the avg aggregation docs

This creates the `COPY AS CURL` and `VIEW IN CONSOLE` buttons and
makes the build test the examples.

Relates to #18160

docs/build.gradle

@@ -35,7 +35,6 @@ buildRestTests.expectedUnconvertedCandidates = [
   'reference/aggregations/bucket/significantterms-aggregation.asciidoc',
   'reference/aggregations/bucket/terms-aggregation.asciidoc',
   'reference/aggregations/matrix/stats-aggregation.asciidoc',
-  'reference/aggregations/metrics/avg-aggregation.asciidoc',
   'reference/aggregations/metrics/cardinality-aggregation.asciidoc',
   'reference/aggregations/metrics/extendedstats-aggregation.asciidoc',
   'reference/aggregations/metrics/geobounds-aggregation.asciidoc',
@@ -405,7 +404,7 @@ buildRestTests.setups['stackoverflow'] = '''
       type: question
       refresh: true
       body: |'''
-      
+
 // Make Kibana strongly connected to elasticsearch and logstash
 // Make Kibana rarer (and therefore higher-ranking) than Javascript
 // Make Javascript strongly connected to jquery and angular
@@ -438,4 +437,27 @@ for (int i = 0; i < 50; i++) {
 }
 buildRestTests.setups['stackoverflow'] += """
 """
-
+// Used by some aggregations
+buildRestTests.setups['exams'] = '''
+  - do:
+    indices.create:
+      index: exams
+      body:
+        settings:
+          number_of_shards: 1
+          number_of_replicas: 1
+        mappings:
+          exam:
+            properties:
+              grade:
+                type: byte
+  - do:
+    bulk:
+      index: exams
+      type: exam
+      refresh: true
+      body: |
+        {"index":{}}
+        {"grade": 100}
+        {"index":{}}
+        {"grade": 50}'''

docs/reference/aggregations/metrics/avg-aggregation.asciidoc

@@ -7,28 +7,30 @@ Assuming the data consists of documents representing exams grades (between 0 and
 
 [source,js]
 --------------------------------------------------
+POST /exams/_search?size=0
 {
     "aggs" : {
         "avg_grade" : { "avg" : { "field" : "grade" } }
     }
 }
 --------------------------------------------------
+// CONSOLE
+// TEST[setup:exams]
 
 The above aggregation computes the average grade over all documents. The aggregation type is `avg` and the `field` setting defines the numeric field of the documents the average will be computed on. The above will return the following:
 
-
 [source,js]
 --------------------------------------------------
 {
     ...
-
     "aggregations": {
         "avg_grade": {
-            "value": 75
+            "value": 75.0
         }
     }
 }
 --------------------------------------------------
+// TESTRESPONSE[s/\.\.\./"took": $body.took,"timed_out": false,"_shards": $body._shards,"hits": $body.hits,/]
 
 The name of the aggregation (`avg_grade` above) also serves as the key by which the aggregation result can be retrieved from the returned response.
 
@@ -38,32 +40,31 @@ Computing the average grade based on a script:
 
 [source,js]
 --------------------------------------------------
+POST /exams/_search?size=0
 {
-    ...,
-
     "aggs" : {
-        "avg_grade" : { 
-            "avg" : { 
+        "avg_grade" : {
+            "avg" : {
                 "script" : {
-                    "inline" : "doc['grade'].value",
-                    "lang" : "painless"
+                    "inline" : "doc.grade.value"
                 }
             }
         }
     }
 }
 --------------------------------------------------
+// CONSOLE
+// TEST[setup:exams]
 
 This will interpret the `script` parameter as an `inline` script with the `painless` script language and no script parameters. To use a file script use the following syntax:
 
 [source,js]
 --------------------------------------------------
+POST /exams/_search?size=0
 {
-    ...,
-
     "aggs" : {
-        "avg_grade" : { 
-            "avg" : { 
+        "avg_grade" : {
+            "avg" : {
                 "script" : {
                     "file": "my_script",
                     "params": {
@@ -75,6 +76,8 @@ This will interpret the `script` parameter as an `inline` script with the `painl
     }
 }
 --------------------------------------------------
+// CONSOLE
+// TEST[setup:exams]
 
 TIP: for indexed scripts replace the `file` parameter with an `id` parameter.
 
@@ -84,20 +87,17 @@ It turned out that the exam was way above the level of the students and a grade
 
 [source,js]
 --------------------------------------------------
+POST /exams/_search?size=0
 {
     "aggs" : {
-        ...
-
-        "aggs" : {
-            "avg_corrected_grade" : {
-                "avg" : {
-                    "field" : "grade",
-                    "script" : {
-                        "lang": "painless",
-                        "inline": "_value * params.correction",
-                        "params" : {
-                            "correction" : 1.2
-                        }
+        "avg_corrected_grade" : {
+            "avg" : {
+                "field" : "grade",
+                "script" : {
+                    "lang": "painless",
+                    "inline": "_value * params.correction",
+                    "params" : {
+                        "correction" : 1.2
                     }
                 }
             }
@@ -105,6 +105,8 @@ It turned out that the exam was way above the level of the students and a grade
     }
 }
 --------------------------------------------------
+// CONSOLE
+// TEST[setup:exams]
 
 ==== Missing value
 
@@ -114,6 +116,7 @@ had a value.
 
 [source,js]
 --------------------------------------------------
+POST /exams/_search?size=0
 {
     "aggs" : {
         "grade_avg" : {
@@ -125,5 +128,7 @@ had a value.
     }
 }
 --------------------------------------------------
+// CONSOLE
+// TEST[setup:exams]
 
 <1> Documents without a value in the `grade` field will fall into the same bucket as documents that have the value `10`.