Docs: Updated docs for 0.20.0 (#9169)

### What problem does this PR solve?

v0.20.0 documents.

### Type of change


- [x] Documentation Update

docs/guides/agent/agent_component_reference/text_processing.mdx

@@ -0,0 +1,38 @@
+---
+sidebar_position: 15
+slug: /text_processing
+---
+
+# Text processing component
+
+A component that merges or splits texts.
+
+---
+
+A **Text processing** component merges or splits texts.
+
+## Configurations
+
+### Method
+
+- Split: Split the text
+- Merge: Merge the text
+
+### Split_ref
+
+Appears only when you select **Split** as method.
+
+The variable to be split. Type `/` to quickly insert variables.
+
+### Script 
+
+Template for the merge. Appears only when you select **Merge** as method. Type `/` to quickly insert variables.
+
+### Delimiters
+
+The delimiter(s) used to split or merge the text.
+
+### Output
+
+The global variable name for the output of the component, which can be referenced by other components in the workflow.
+