[ES|QL] Adds inline docs for the SAMPLE command (#224806)

This PR adds inline docs for the CHANGE POINT command. It mimics the
content currently at
https://www.elastic.co/docs/reference/query-languages/esql/commands/processing-commands#esql-sample

<img width="526" alt="image"
src="https://github.com/user-attachments/assets/2eb9e99c-d768-4149-98b1-ec90717dc51b"
/>

Closes: https://github.com/elastic/docs-content/issues/1825

src/platform/packages/private/kbn-language-documentation/src/sections/esql_documentation_sections.tsx

@@ -574,6 +574,56 @@ FROM employees
         />
       ),
     },
+    {
+      label: i18n.translate('languageDocumentation.documentationESQL.sampleCommand', {
+        defaultMessage: 'SAMPLE',
+      }),
+      preview: true,
+      description: (
+        <Markdown
+          openLinksInNewTab={true}
+          markdownContent={i18n.translate(
+            'languageDocumentation.documentationESQL.sampleCommand.markdown',
+            {
+              defaultMessage: `### SAMPLE
+The \`SAMPLE\` command samples a fraction of the table rows. 
+
+**Syntax**
+
+\`\`\` esql
+SAMPLE probability
+\`\`\` 
+
+**Parameters**
+
+* \`probability\`: The probability that a row is included in the sample. The value must be between 0 and 1, exclusive.
+
+**Example**
+
+The following example shows the detection of a step change:
+
+\`\`\` esql
+FROM employees
+| KEEP emp_no
+| SAMPLE 0.05
+\`\`\` 
+
+| emp_no:integer |
+|----------------|
+| 10018          |
+| 10024          |
+| 10062          |
+| 10081          |
+
+`,
+              ignoreTag: true,
+              description:
+                'Text is in markdown. Do not translate function names, special characters, or field names like sum(bytes)',
+            }
+          )}
+        />
+      ),
+    },
     {
       label: i18n.translate('languageDocumentation.documentationESQL.sort', {
         defaultMessage: 'SORT',