Add anchor to doc link in old index check (#37724)

The check for old indices did not include an anchor to the specific
part of the breaking changes list addressing the breaking change, unlike
all the other deprecation warnings. This commit adds an anchor to that
link.

Author: gwbrown

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/IndexDeprecationChecks.java

@@ -117,8 +117,8 @@ static DeprecationIssue oldIndicesCheck(IndexMetaData indexMetaData) {
             } else {
                 return new DeprecationIssue(DeprecationIssue.Level.CRITICAL,
                     "Index created before 6.0",
-                    "https://www.elastic.co/guide/en/elasticsearch/reference/master/" +
-                        "breaking-changes-7.0.html",
+                    "https://www.elastic.co/guide/en/elasticsearch/reference/master/breaking-changes-7.0.html" +
+                        "#_indices_created_before_7_0",
                     "This index was created using version: " + createdWith);
             }
 

x-pack/plugin/deprecation/src/test/java/org/elasticsearch/xpack/deprecation/IndexDeprecationChecksTests.java

@@ -37,8 +37,8 @@ public void testOldIndicesCheck() {
             .build();
         DeprecationIssue expected = new DeprecationIssue(DeprecationIssue.Level.CRITICAL,
             "Index created before 6.0",
-            "https://www.elastic.co/guide/en/elasticsearch/reference/master/" +
-                "breaking-changes-7.0.html",
+            "https://www.elastic.co/guide/en/elasticsearch/reference/master/breaking-changes-7.0.html" +
+                "#_indices_created_before_7_0",
             "This index was created using version: " + createdWith);
         List<DeprecationIssue> issues = DeprecationChecks.filterChecks(INDEX_SETTINGS_CHECKS, c -> c.apply(indexMetaData));
         assertEquals(singletonList(expected), issues);
@@ -73,8 +73,8 @@ public void testMultipleTypesCheckWithDefaultMapping() throws IOException {
 
         DeprecationIssue expected = new DeprecationIssue(DeprecationIssue.Level.CRITICAL,
             "Index created before 6.0",
-            "https://www.elastic.co/guide/en/elasticsearch/reference/master/" +
-                "breaking-changes-7.0.html",
+            "https://www.elastic.co/guide/en/elasticsearch/reference/master/breaking-changes-7.0.html" +
+                "#_indices_created_before_7_0",
             "This index was created using version: " + createdWith);
         List<DeprecationIssue> issues = DeprecationChecks.filterChecks(INDEX_SETTINGS_CHECKS, c -> c.apply(indexMetaData));
         assertEquals(singletonList(expected), issues);