Remove "suggest" from Indices Stats and Node Stats REST API specs

[russcam]

Whilst going through #29635, I've noticed that the REST API spec for node stats contains "suggest" as an index_metric value

elasticsearch/rest-api-spec/src/main/resources/rest-api-spec/api/nodes.stats.json

Line 23 in 0a16e41

"options" : ["_all", "completion", "docs", "fielddata", "query_cache", "flush", "get", "indexing", "merge", "request_cache", "refresh", "search", "segments", "store", "warmer", "suggest"],

and indices stats contains "suggest" for a metric value

elasticsearch/rest-api-spec/src/main/resources/rest-api-spec/api/indices.stats.json

Line 20 in 7674de9

"options" : ["_all", "completion", "docs", "fielddata", "query_cache", "flush", "get", "indexing", "merge", "request_cache", "refresh", "search", "segments", "store", "warmer", "suggest"],

I believe both should no longer be there. I don't think that it'll be possible to delete these in 7.x however, because @elastic/es-clients use the specs to generate code, so removing may be a backwards breaking change.

Based on

elasticsearch/server/src/main/java/org/elasticsearch/rest/action/admin/indices/RestIndicesStatsAction.java

Lines 61 to 76 in 58516fa

	metrics.put("docs", r -> r.docs(true));
	metrics.put("store", r -> r.store(true));
	metrics.put("indexing", r -> r.indexing(true));
	metrics.put("search", r -> r.search(true));
	metrics.put("get", r -> r.get(true));
	metrics.put("merge", r -> r.merge(true));
	metrics.put("refresh", r -> r.refresh(true));
	metrics.put("flush", r -> r.flush(true));
	metrics.put("warmer", r -> r.warmer(true));
	metrics.put("query_cache", r -> r.queryCache(true));
	metrics.put("segments", r -> r.segments(true));
	metrics.put("fielddata", r -> r.fieldData(true));
	metrics.put("completion", r -> r.completion(true));
	metrics.put("request_cache", r -> r.requestCache(true));
	metrics.put("recovery", r -> r.recovery(true));
	metrics.put("translog", r -> r.translog(true));

and

elasticsearch/server/src/main/java/org/elasticsearch/action/admin/indices/stats/CommonStatsFlags.java

Lines 228 to 245 in 0a16e41

	public enum Flag {
	Store("store", 0),
	Indexing("indexing", 1),
	Get("get", 2),
	Search("search", 3),
	Merge("merge", 4),
	Flush("flush", 5),
	Refresh("refresh", 6),
	QueryCache("query_cache", 7),
	FieldData("fielddata", 8),
	Docs("docs", 9),
	Warmer("warmer", 10),
	Completion("completion", 11),
	Segments("segments", 12),
	Translog("translog", 13),
	// 14 was previously used for Suggest
	RequestCache("request_cache", 15),
	Recovery("recovery", 16);

It also looks like the REST specs are missing "recovery" and "translog", which can be safely added to the specs.

[elasticmachine]

Pinging @elastic/es-core-infra