[DOCS] Adding headers in TOC for aggregation docs. (#66604)

Author: Adam Locke

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

@@ -56,7 +56,7 @@ will be removed in the future.
 ==================================
 
 [[calendar_intervals]]
-===== Calendar intervals
+==== Calendar intervals
 
 Calendar-aware intervals are configured with the `calendar_interval` parameter.
 You can specify calendar intervals using the unit name, such as `month`, or as a
@@ -173,7 +173,7 @@ POST /sales/_search?size=0
 // NOTCONSOLE
 
 [[fixed_intervals]]
-===== Fixed intervals
+==== Fixed intervals
 
 Fixed intervals are configured with the `fixed_interval` parameter.
 
@@ -267,7 +267,7 @@ POST /sales/_search?size=0
 // NOTCONSOLE
 
 [[datehistogram-aggregation-notes]]
-===== Notes
+==== Date histogram usage notes
 
 In all cases, when the specified end time does not exist, the actual end time is
 the closest available time after the specified end.
@@ -282,17 +282,17 @@ As always, rigorous testing, especially around time-change events, will ensure
 that your time interval specification is
 what you intend it to be.
 
-WARNING:
-To avoid unexpected results, all connected servers and clients must sync to a
-reliable network time service.
+WARNING: To avoid unexpected results, all connected servers and clients must
+sync to a reliable network time service.
 
-NOTE: fractional time values are not supported, but you can address this by
+NOTE: Fractional time values are not supported, but you can address this by
 shifting to another time unit (e.g., `1.5h` could instead be specified as `90m`).
 
 NOTE: You can also specify time values using abbreviations supported by
 <<time-units,time units>> parsing.
 
-===== Keys
+[[datehistogram-aggregation-keys]]
+==== Keys
 
 Internally, a date is represented as a 64 bit number representing a timestamp
 in milliseconds-since-the-epoch (01/01/1970 midnight UTC). These timestamps are
@@ -353,7 +353,8 @@ Response:
 --------------------------------------------------
 // TESTRESPONSE[s/\.\.\./"took": $body.took,"timed_out": false,"_shards": $body._shards,"hits": $body.hits,/]
 
-===== Time zone
+[[datehistogram-aggregation-time-zone]]
+==== Time zone
 
 {es} stores date-times in Coordinated Universal Time (UTC). By default, all bucketing and
 rounding is also done in UTC. Use the `time_zone` parameter to indicate
@@ -489,7 +490,7 @@ shorter intervals, like a `fixed_interval` of `12h`, where you'll have only a 11
 bucket on the morning of 27 March when the DST shift happens.
 
 [[search-aggregations-bucket-datehistogram-offset]]
-===== Offset
+==== Offset
 
 // tag::offset-explanation[]
 Use the `offset` parameter to change the start value of each bucket by the
@@ -562,7 +563,8 @@ NOTE: The start `offset` of each bucket is calculated after `time_zone`
 adjustments have been made.
 // end::offset-note[]
 
-===== Keyed Response
+[[date-histogram-keyed-response]]
+==== Keyed Response
 
 Setting the `keyed` flag to `true` associates a unique string key with each
 bucket and returns the ranges as a hash rather than an array:
@@ -616,7 +618,8 @@ Response:
 --------------------------------------------------
 // TESTRESPONSE[s/\.\.\./"took": $body.took,"timed_out": false,"_shards": $body._shards,"hits": $body.hits,/]
 
-===== Scripts
+[[date-histogram-scripts]]
+==== Scripts
 
 As with the normal <<search-aggregations-bucket-histogram-aggregation,histogram>>,
 both document-level scripts and
@@ -632,6 +635,7 @@ For more information, see
 <<search-aggregations-bucket-histogram-aggregation-extended-bounds,`Extended Bounds`>> and
 <<search-aggregations-bucket-histogram-aggregation-hard-bounds,`Hard Bounds`>>.
 
+[[date-histogram-missing-value]]
 ===== Missing value
 
 The `missing` parameter defines how to treat documents that are missing a value.
@@ -658,19 +662,20 @@ POST /sales/_search?size=0
 <1> Documents without a value in the `publish_date` field will fall into the
 same bucket as documents that have the value `2000-01-01`.
 
+[[date-histogram-order]]
 ===== Order
 
 By default the returned buckets are sorted by their `key` ascending, but you can
 control the order using
 the `order` setting. This setting supports the same `order` functionality as
 <<search-aggregations-bucket-terms-aggregation-order,`Terms Aggregation`>>.
 
+[[date-histogram-aggregate-scripts]]
 ===== Using a script to aggregate by day of the week
 
 When you need to aggregate the results by day of the week, use a script that
 returns the day of the week:
 
-
 [source,console,id=datehistogram-aggregation-script-example]
 --------------------------------------------------
 POST /sales/_search?size=0

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

@@ -82,6 +82,7 @@ The response for the above aggregation:
 
 [discrete]
 [role="xpack"]
+[[geobounds-aggregation-geo-shape]]
 ==== Geo Bounds Aggregation on `geo_shape` fields
 
 The Geo Bounds Aggregation is also supported on `geo_shape` fields.

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

@@ -150,6 +150,7 @@ The response for the above aggregation:
 
 [discrete]
 [role="xpack"]
+[[geocentroid-aggregation-geo-shape]]
 ==== Geo Centroid Aggregation on `geo_shape` fields
 
 The centroid metric for geo-shapes is more nuanced than for points. The centroid of a specific aggregation bucket