Add documentation of RequestMapping about SpEL

Signed-off-by: 秦利斌 <68638598+Allan-QLB@users.noreply.github.com>

framework-docs/modules/ROOT/pages/web/webflux/controller/ann-requestmapping.adoc

@@ -237,7 +237,7 @@ Kotlin::
 URI path patterns can also have embedded `${...}` placeholders that are resolved on startup
 by using `PropertySourcesPlaceholderConfigurer` against local, system, environment, and
 other property sources. You can use this, for example, to parameterize a base URL based on
-some external configuration.
+some external configuration. SpEL expression `#{...}` is also supported in URI path pattern by default.
 
 NOTE: Spring WebFlux uses `PathPattern` and the `PathPatternParser` for URI path matching support.
 Both classes are located in `spring-web` and are expressly designed for use with HTTP URL

framework-docs/modules/ROOT/pages/web/webmvc/mvc-controller/ann-requestmapping.adoc

@@ -220,7 +220,7 @@ Kotlin::
 URI path patterns can also have embedded `${...}` placeholders that are resolved on startup
 by using `PropertySourcesPlaceholderConfigurer` against local, system, environment, and
 other property sources. You can use this, for example, to parameterize a base URL based on
-some external configuration.
+some external configuration. SpEL expression `#{...}` is also supported in URI path pattern by default.
 
 
 [[mvc-ann-requestmapping-pattern-comparison]]

spring-web/src/main/java/org/springframework/web/bind/annotation/RequestMapping.java

@@ -109,12 +109,16 @@ public @interface RequestMapping {
 	 * At the method level, relative paths (for example, {@code "edit"}) are supported
 	 * within the primary mapping expressed at the type level.
 	 * Path mapping URIs may contain placeholders (for example, <code>"/${profile_path}"</code>).
+	 * By default, SpEL expression is also supported (for example {@code "/profile/#{@bean.property}"}).
 	 * <p><b>Supported at the type level as well as at the method level!</b>
 	 * When used at the type level, all method-level mappings inherit
 	 * this primary mapping, narrowing it for a specific handler method.
 	 * <p><strong>NOTE</strong>: A handler method that is not mapped to any path
 	 * explicitly is effectively mapped to an empty path.
 	 * @since 4.2
+	 * @see org.springframework.beans.factory.config.EmbeddedValueResolver
+	 * @see org.springframework.context.expression.StandardBeanExpressionResolver
+	 * @see org.springframework.context.support.AbstractApplicationContext
 	 */
 	@AliasFor("value")
 	String[] path() default {};