[exporter/elasticsearch] Update README (open-telemetry#32221)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
Correct some errors and add more details.

No functional change, no changelog needed.

---------

Co-authored-by: Curtis Robert <crobert@splunk.com>
Co-authored-by: Alex Boten <223565+codeboten@users.noreply.github.com>

exporter/elasticsearchexporter/README.md

@@ -12,32 +12,32 @@
 [contrib]: https://github.com/open-telemetry/opentelemetry-collector-releases/tree/main/distributions/otelcol-contrib
 <!-- end autogenerated section -->
 
-This exporter supports sending OpenTelemetry logs to [Elasticsearch](https://www.elastic.co/elasticsearch).
+This exporter supports sending OpenTelemetry logs and traces to [Elasticsearch](https://www.elastic.co/elasticsearch).
 
 ## Configuration options
 
-- `endpoints`: List of Elasticsearch URLs. If endpoints and cloudid is missing, the
+- `endpoints`: List of Elasticsearch URLs. If `endpoints` and `cloudid` are missing, the
   ELASTICSEARCH_URL environment variable will be used.
 - `cloudid` (optional):
   [ID](https://www.elastic.co/guide/en/cloud/current/ec-cloud-id.html) of the
   Elastic Cloud Cluster to publish events to. The `cloudid` can be used instead
   of `endpoints`.
 - `num_workers` (optional): Number of workers publishing bulk requests concurrently.
-- `index`: The
+- `index` (DEPRECATED, please use `logs_index` for logs, `traces_index` for traces): The
   [index](https://www.elastic.co/guide/en/elasticsearch/reference/current/indices.html)
-  or [datastream](https://www.elastic.co/guide/en/elasticsearch/reference/current/data-streams.html)
-  name to publish events to. The default value is `logs-generic-default`. Note: To better differentiate between log indexes and traces indexes, `index` option are deprecated and replaced with below `logs_index`
+  or [data stream](https://www.elastic.co/guide/en/elasticsearch/reference/current/data-streams.html)
+  name to publish events to. The default value is `logs-generic-default`.
 - `logs_index`: The
   [index](https://www.elastic.co/guide/en/elasticsearch/reference/current/indices.html)
-  or [datastream](https://www.elastic.co/guide/en/elasticsearch/reference/current/data-streams.html)
+  or [data stream](https://www.elastic.co/guide/en/elasticsearch/reference/current/data-streams.html)
   name to publish events to. The default value is `logs-generic-default`
 - `logs_dynamic_index` (optional):
   takes resource or log record attribute named `elasticsearch.index.prefix` and `elasticsearch.index.suffix`
   resulting dynamically prefixed / suffixed indexing based on `logs_index`. (priority: resource attribute > log record attribute)
   - `enabled`(default=false): Enable/Disable dynamic index for log records
 - `traces_index`: The
   [index](https://www.elastic.co/guide/en/elasticsearch/reference/current/indices.html)
-  or [datastream](https://www.elastic.co/guide/en/elasticsearch/reference/current/data-streams.html)
+  or [data stream](https://www.elastic.co/guide/en/elasticsearch/reference/current/data-streams.html)
   name to publish traces to. The default value is `traces-generic-default`.
 - `traces_dynamic_index` (optional):
   takes resource or span attribute named `elasticsearch.index.prefix` and `elasticsearch.index.suffix`
@@ -49,14 +49,12 @@ This exporter supports sending OpenTelemetry logs to [Elasticsearch](https://www
                                 The last string appended belongs to the date when the data is being generated.
   - `prefix_separator`(default=`-`): Set a separator between logstash_prefix and date.
   - `date_format`(default=`%Y.%m.%d`): Time format (based on strftime) to generate the second part of the Index name.
-- `pipeline` (optional): Optional [Ingest Node](https://www.elastic.co/guide/en/elasticsearch/reference/current/ingest.html)
-  pipeline ID used for processing documents published by the exporter.
-- `flush`: Event bulk buffer flush settings
-  - `bytes` (default=5242880): Write buffer flush limit.
-  - `interval` (default=30s): Write buffer time limit.
-- `retry`: Event retry settings
-  - `enabled` (default=true): Enable/Disable event retry on error. Retry
-    support is enabled by default.
+- `pipeline` (optional): Optional [Ingest pipeline](https://www.elastic.co/guide/en/elasticsearch/reference/current/ingest.html) ID used for processing documents published by the exporter.
+- `flush`: Event bulk indexer buffer flush settings
+  - `bytes` (default=5242880): Write buffer flush size limit.
+  - `interval` (default=30s): Write buffer flush time limit.
+- `retry`: Elasticsearch bulk request retry settings
+  - `enabled` (default=true): Enable/Disable request retry on error. Failed requests are retried with exponential backoff.
   - `max_requests` (default=3): Number of HTTP request retries.
   - `initial_interval` (default=100ms): Initial waiting time if a HTTP request failed.
   - `max_interval` (default=1m): Max waiting time if a HTTP request failed.
@@ -81,19 +79,19 @@ This exporter supports sending OpenTelemetry logs to [Elasticsearch](https://www
 - `sending_queue`
   - `enabled` (default = false)
   - `num_consumers` (default = 10): Number of consumers that dequeue batches; ignored if `enabled` is `false`
-  - `queue_size` (default = 1000): Maximum number of batches kept in memory before data; ignored if `enabled` is `false`;
+  - `queue_size` (default = 1000): Maximum number of batches kept in queue; ignored if `enabled` is `false`;
 ### HTTP settings
 
-- `read_buffer_size` (default=0): Read buffer size.
-- `write_buffer_size` (default=0): Write buffer size used when.
+- `read_buffer_size` (default=0): Read buffer size of HTTP client.
+- `write_buffer_size` (default=0): Write buffer size of HTTP client.
 - `timeout` (default=90s): HTTP request time limit.
-- `headers` (optional): Headers to be send with each HTTP request.
+- `headers` (optional): Headers to be sent with each HTTP request.
 
 ### Security and Authentication settings
 
 - `user` (optional): Username used for HTTP Basic Authentication.
 - `password` (optional): Password used for HTTP Basic Authentication.
-- `api_key` (optional):  Authorization [API Key](https://www.elastic.co/guide/en/elasticsearch/reference/current/security-api-create-api-key.html).
+- `api_key` (optional):  Authorization [API Key](https://www.elastic.co/guide/en/elasticsearch/reference/current/security-api-create-api-key.html) in "encoded" format.
 
 ### TLS settings
 - `ca_file` (optional): Root Certificate Authority (CA) certificate, for
@@ -102,7 +100,6 @@ This exporter supports sending OpenTelemetry logs to [Elasticsearch](https://www
 - `key_file` (optional): Client TLS key.
 - `insecure` (optional): In gRPC when set to true, this is used to disable the client transport security. In HTTP, this disables verifying the server's certificate chain and host name.
 - `insecure_skip_verify` (optional): Will enable TLS but not verify the certificate.
-  is enabled.
 
 ### Node Discovery