docs: add string_split processor to Cloud (#547)

* docs: add string_split processor to Cloud

Added new string_split processor (available in Redpanda Connect 4.86.0)
to Cloud documentation.

Changes:
- Created processor page with include directive from redpanda-connect
- Added to navigation (alphabetically after split)
- Added to April 2026 what's new section
- Included page alias for backward compatibility

The string_split processor splits strings into multiple parts using a
delimiter, creating new messages or fields for each part.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

* Fix nav ordering for string_split processor

Move string_split processor to correct alphabetical position after
sql_select (before switch). Previously placed between split and
sql_insert which broke alphabetical ordering.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: JakeSCahill

modules/ROOT/nav.adoc

@@ -307,6 +307,7 @@
 **** xref:develop:connect/components/processors/sql_insert.adoc[]
 **** xref:develop:connect/components/processors/sql_raw.adoc[]
 **** xref:develop:connect/components/processors/sql_select.adoc[]
+**** xref:develop:connect/components/processors/string_split.adoc[]
 **** xref:develop:connect/components/processors/switch.adoc[]
 **** xref:develop:connect/components/processors/sync_response.adoc[]
 **** xref:develop:connect/components/processors/text_chunker.adoc[]

modules/develop/pages/connect/components/processors/string_split.adoc

@@ -0,0 +1,4 @@
+= string_split
+:page-aliases: components:processors/string_split.adoc
+
+include::redpanda-connect:components:processors/string_split.adoc[tag=single-source]

modules/get-started/pages/whats-new-cloud.adoc

@@ -19,6 +19,11 @@ GBAC is available for BYOC and Dedicated clusters. In addition to the predefined
 
 Serverless clusters now support up to 100 Redpanda Connect pipelines and 100 MCP servers. See xref:get-started:cluster-types/serverless.adoc#_serverless_usage_limits[Serverless usage limits].
 
+=== Redpanda Connect updates
+
+* Processors:
+** xref:develop:connect/components/processors/string_split.adoc[string_split]: Splits strings into multiple parts using a delimiter, creating new messages or fields for each part.
+
 == March 2026
 
 === Redpanda Connect updates