Make max length of SpEL expressions in an ApplicationContext configurable

This commit introduces support for a Spring property named
`spring.context.expression.maxLength`. When set, the value of that
property is used internally in StandardBeanExpressionResolver to
configure the SpelParserConfiguration used when evaluating String
values in bean definitions, @⁠Value, etc.

Closes gh-31952

framework-docs/modules/ROOT/pages/appendix.adoc

@@ -28,6 +28,11 @@ JavaBeans `Introspector`. See
 {spring-framework-api}++/beans/StandardBeanInfoFactory.html#IGNORE_BEANINFO_PROPERTY_NAME++[`CachedIntrospectionResults`]
 for details.
 
+| `spring.context.expression.maxLength`
+| The maximum length for
+xref:core/expressions/evaluation.adoc#expressions-parser-configuration[Spring Expression Language]
+expressions used in XML bean definitions, `@Value`, etc.
+
 | `spring.expression.compiler.mode`
 | The mode to use when compiling expressions for the
 xref:core/expressions/evaluation.adoc#expressions-compiler-configuration[Spring Expression Language].

framework-docs/modules/ROOT/pages/core/expressions/evaluation.adoc

@@ -380,6 +380,15 @@ Kotlin::
 ----
 ======
 
+By default, a SpEL expression cannot contain more than 10,000 characters; however, the
+`maxExpressionLength` is configurable. If you create a `SpelExpressionParser`
+programmatically, you can specify a custom `maxExpressionLength` when creating the
+`SpelParserConfiguration` that you provide to the `SpelExpressionParser`. If you wish to
+set the `maxExpressionLength` used for parsing SpEL expressions within an
+`ApplicationContext` -- for example, in XML bean definitions, `@Value`, etc. -- you can
+set a JVM system property or Spring property named `spring.context.expression.maxLength`
+to the maximum expression length needed by your application (see
+xref:appendix.adoc#appendix-spring-properties[Supported Spring Properties]).
 
 
 [[expressions-spel-compilation]]