Add example to Extract fields RegExp option (#96946)

Co-authored-by: Leon Sorokin <leeoniya@gmail.com>

docs/sources/panels-visualizations/query-transform-data/transform-data/index.md

@@ -340,7 +340,7 @@ Use this transformation to select a source of data and extract content from it i
 - **Format** - Choose one of the following:
   - **JSON** - Parse JSON content from the source.
   - **Key+value pairs** - Parse content in the format 'a=b' or 'c:d' from the source.
-  - **RegExp** - Parse content using a regular expression with [named capturing group(s)](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Named_capturing_group).
+  - **RegExp** - Parse content using a regular expression with [named capturing group(s)](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Named_capturing_group) like `/(?<NewField>.*)/`.
   - **Auto** - Discover fields automatically.
 - **Replace All Fields** - (Optional) Select this option to hide all other fields and display only your calculated field in the visualization.
 - **Keep Time** - (Optional) Available only if **Replace All Fields** is true. Keeps the time field in the output.

public/app/features/transformers/docs/content.ts

@@ -243,7 +243,7 @@ Use this transformation to select a source of data and extract content from it i
 - **Format** - Choose one of the following:
   - **JSON** - Parse JSON content from the source.
   - **Key+value pairs** - Parse content in the format 'a=b' or 'c:d' from the source.
-  - **RegExp** - Parse content using a regular expression with [named capturing group(s)](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Named_capturing_group).
+  - **RegExp** - Parse content using a regular expression with [named capturing group(s)](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Named_capturing_group) like \`/(?<New_Field>.*)/\`.
   - **Auto** - Discover fields automatically.
 - **Replace All Fields** - (Optional) Select this option to hide all other fields and display only your calculated field in the visualization.
 - **Keep Time** - (Optional) Available only if **Replace All Fields** is true. Keeps the time field in the output.