ESQL: Add example of regex REPLACE

x-pack/plugin/esql/qa/testFixtures/src/main/resources/docs.csv-spec

@@ -335,20 +335,6 @@ date_string:keyword | date:date
 // end::dateParse-result[]
 ;
 
-docsReplace
-//tag::replaceString[]
-ROW str = "Hello World"
-| EVAL str = REPLACE(str, "World", "Universe")
-| KEEP str
-// end::replaceString[]
-;
-
-//tag::replaceString-result[]
-str:keyword
-Hello Universe
-// end::replaceString-result[]
-;
-
 docsCase
 // tag::case[]
 FROM employees

x-pack/plugin/esql/qa/testFixtures/src/main/resources/string.csv-spec

@@ -1223,6 +1223,33 @@ first_name:keyword | result:keyword
 Alejandro          | null
 ;
 
+docsReplaceText
+//tag::replaceString[]
+ROW str = "Hello World"
+| EVAL str = REPLACE(str, "World", "Universe")
+// end::replaceString[]
+;
+
+//tag::replaceString-result[]
+str:keyword
+Hello Universe
+// end::replaceString-result[]
+;
+
+docsReplaceRegex
+//tag::replaceRegex[]
+ROW str = "Hello World"
+| EVAL str = REPLACE(str, "\\s+", "")
+// end::replaceRegex[]
+;
+
+//tag::replaceRegex-result[]
+str:keyword
+HelloWorld
+// end::replaceRegex-result[]
+;
+
+
 left
 // tag::left[]
 FROM employees

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/scalar/string/Replace.java

@@ -50,11 +50,18 @@ public class Replace extends EsqlScalarFunction {
         description = """
             The function substitutes in the string `str` any match of the regular expression `regex`
             with the replacement string `newStr`.""",
-        examples = @Example(
-            file = "docs",
-            tag = "replaceString",
-            description = "This example replaces any occurrence of the word \"World\" with the word \"Universe\":"
-        )
+        examples = {
+            @Example(
+                file = "string",
+                tag = "replaceString",
+                description = "This example replaces any occurrence of the word \"World\" with the word \"Universe\":"
+            ),
+            @Example(
+                file = "string",
+                tag = "replaceRegex",
+                description = "This example removes all spaces:"
+            )
+        }
     )
     public Replace(
         Source source,