Issue: SPR-13512

Issue: SPR-13518

Issue: SPR-6706

Issue: SPR-13725

Update assertion to validate the proper exception type is thrown.

Issue: SPR-13723

Also taking the opportunity to refine the "No Scope registered" exception message a bit.

Issue: SPR-13681

Issue: SPR-13712

Issue: SPR-13720

When the plus operator is used between strings in a SpEL
expression and that expression is compiled, it is
important to include a cast if computation of any of
the operands isn't obviously leaving strings on the
stack. Likewise if the stack contents are known to
be strings, a cast should not be included.

Issue: SPR-12426

Issue: SPR-13721

Prior to this commit, range requests would be served by
ResourceHttpRequestHandler by partially reading the inputstream of
static resources. In case of resources contained in ZIP/JAR containers,
InputStreams may not fill the entire read buffer when calling
`inputStream.read(byte[])`. This was the case when using Spring Boot's
ZipInflaterInputStream - this would then not read the entire file
content and would close the response without writing the expected body
length indicated in the "Content-Length" header.

This commit makes sure that the whole resource is read.

Issue: SPR-13661

Issue: SPR-13695

This also turns @ManagedNotification into a repeatable annotation and consistently applies findAnnotation/getRepeatableAnnotations.

Issue: SPR-13700

Issue: SPR-12926

Issue: SPR-13704

Prior to this commit, when adding a ShallowEtagHeaderFilter to an
application, the ServletResponse would be wrapped by a
ContentCachingResponseWrapper. When any part of the Spring
infrastructure calls `flushBuffer` on the wrapped response, the call is
delegated to the actual response, which is committed. It's not possible
to alter the response (headers, content) anymore - the ETag filter can't
act.

This change prevents the `flushBuffer` call to be delegated and only
commits the underlying response once the cached content is copied to the
actual response stream.

Issue: SPR-13717

With this change the MapAccessor now extends CompilablePropertyAccessor
rather than just PropertyAccessor. This means that any expression that
ends up using the MapAccessor is now compilable for fast performance.

Issue: SPR-13638

* pr/926:
  Add link in jsp tag library

Closes gh-926

Issue: SPR-13678

* pr/923:
  Remove invalid underscore

Closes gh-923

* pr/922:
  Add quotes around attribute value

Closes gh-922

This upgrade includes AutoCloseable support for HtmlUnit WebConnections as introduced in 2.19, while remaining compatible with 2.18.

Issue: SPR-13686