Remove :standard-include-class-name-pattern: from User Guide

This commit replaces the outdated and hardcoded
:standard-include-class-name-pattern: from the User Guide and replaces
it with plain English describing the supported prefix and suffixes.

Issue: #1354

Author: sbrannen

documentation/src/docs/asciidoc/link-attributes.adoc

@@ -23,7 +23,6 @@ endif::[]
 :TestEngine:                        {javadoc-root}/org/junit/platform/engine/TestEngine.html[TestEngine]
 :DiscoverySelectors_selectMethod:   {javadoc-root}/org/junit/platform/engine/discovery/DiscoverySelectors.html#selectMethod-java.lang.String-[selectMethod(String) in DiscoverySelectors]
 :TestExecutionListener:             {javadoc-root}/org/junit/platform/launcher/TestExecutionListener.html[TestExecutionListener]
-:standard-include-class-name-pattern: ^.*Tests?$
 //
 :api-package:                       {javadoc-root}/org/junit/jupiter/api/package-summary.html[org.junit.jupiter.api]
 :extension-api-package:             {javadoc-root}/org/junit/jupiter/api/extension/package-summary.html[org.junit.jupiter.api.extension]

documentation/src/docs/asciidoc/user-guide/running-tests.adoc

@@ -635,8 +635,8 @@ include::{testDir}/example/JUnit4SuiteDemo.java[tags=user_guide]
 ----
 
 The `JUnit4SuiteDemo` will discover and run all tests in the `example` package
-and its subpackages. By default, it will only include test classes whose names match the
-pattern `{standard-include-class-name-pattern}`.
+and its subpackages. By default, it will only include test classes whose names
+either begin with `Test` or end with `Test` or `Tests`.
 
 .Additional Configuration Options
 NOTE: There are more configuration options for discovering and filtering tests than just