KAFKA-20519 Fix broken links in configuration option docs (#22127)

Several items in the Kafka docs configuration reference seem to include
links to other parts of the documentation that do not work anymore on
the new website. This PR updates them in the Java code so that they
could be fixed in the next release. It is using the pattern already used
for some other configuration otpions, so hopefully it is the correct
one.

Reviewers: Chia-Ping Tsai <chia7712@gmail.com>

Author: scholzj

clients/src/main/java/org/apache/kafka/common/config/TopicConfig.java

@@ -53,7 +53,7 @@ public class TopicConfig {
         "we would fsync after every message; if it were 5 we would fsync after every five messages. " +
         "In general we recommend you not set this and use replication for durability and allow the " +
         "operating system's background flush capabilities as it is more efficient. This setting can " +
-        "be overridden on a per-topic basis (see <a href=\"#topicconfigs\">the per-topic configuration section</a>).";
+        "be overridden on a per-topic basis (see <a href=\"https://kafka.apache.org/documentation/#topicconfigs\">the per-topic configuration section</a>).";
 
     public static final String FLUSH_MS_CONFIG = "flush.ms";
     public static final String FLUSH_MS_DOC = "This setting allows specifying a time interval at which we will " +
@@ -124,7 +124,7 @@ public class TopicConfig {
 
     public static final String DELETE_RETENTION_MS_CONFIG = "delete.retention.ms";
     public static final String DELETE_RETENTION_MS_DOC = "The amount of time to retain delete tombstone markers " +
-        "for <a href=\"#compaction\">log compacted</a> topics. This setting also gives a bound " +
+        "for <a href=\"https://kafka.apache.org/documentation/#compaction\">log compacted</a> topics. This setting also gives a bound " +
         "on the time in which a consumer must complete a read if they begin from offset 0 " +
         "to ensure that they get a valid snapshot of the final stage (otherwise delete " +
         "tombstones may be collected before they complete their scan).";
@@ -139,7 +139,7 @@ public class TopicConfig {
 
     public static final String MIN_CLEANABLE_DIRTY_RATIO_CONFIG = "min.cleanable.dirty.ratio";
     public static final String MIN_CLEANABLE_DIRTY_RATIO_DOC = "This configuration controls how frequently " +
-        "the log compactor will attempt to clean the log (assuming <a href=\"#compaction\">log " +
+        "the log compactor will attempt to clean the log (assuming <a href=\"https://kafka.apache.org/documentation/#compaction\">log " +
         "compaction</a> is enabled). By default we will avoid cleaning a log where more than " +
         "50% of the log has been compacted. This ratio bounds the maximum space wasted in " +
         "the log by duplicates (at 50% at most 50% of the log could be duplicates). A " +
@@ -156,7 +156,7 @@ public class TopicConfig {
     public static final String CLEANUP_POLICY_DOC = "This config designates the retention policy to " +
         "use on log segments. The \"delete\" policy (which is the default) will discard old segments " +
         "when their retention time or size limit has been reached. The \"compact\" policy will enable " +
-        "<a href=\"#compaction\">log compaction</a>, which retains the latest value for each key. " +
+        "<a href=\"https://kafka.apache.org/documentation/#compaction\">log compaction</a>, which retains the latest value for each key. " +
         "It is also possible to specify both policies in a comma-separated list (e.g. \"delete,compact\"). " +
         "In this case, old segments will be discarded per the retention time and size configuration, " +
         "while retained segments will be compacted. " +
@@ -185,7 +185,7 @@ public class TopicConfig {
         "A typical scenario would be to create a topic with a replication factor of 3, " +
         "set <code>min.insync.replicas</code> to 2, and produce with <code>acks</code> of \"all\". " +
         "This ensures that a majority of replicas must persist a write before it's considered successful by the producer and it's visible to consumers." +
-        "<p>Note that when the Eligible Leader Replicas feature is enabled, the semantics of this config changes. Please refer to <a href=\"#eligible_leader_replicas\">the ELR section</a> for more info.</p>";
+        "<p>Note that when the Eligible Leader Replicas feature is enabled, the semantics of this config changes. Please refer to <a href=\"https://kafka.apache.org/documentation/#eligible_leader_replicas\">the ELR section</a> for more info.</p>";
 
     public static final String COMPRESSION_TYPE_CONFIG = "compression.type";
     public static final String COMPRESSION_TYPE_DOC = "Specify the final compression type for a given topic. " +

clients/src/main/java/org/apache/kafka/common/config/internals/BrokerSecurityConfigs.java

@@ -55,7 +55,7 @@ public class BrokerSecurityConfigs {
             " from the client certificate to short name. The rules are evaluated in order and the first rule that matches" +
             " a principal name is used to map it to a short name. Any later rules in the list are ignored. By default," +
             " distinguished name of the X.500 certificate will be the principal. For more details on the format please" +
-            " see <a href=\"#security_authz\"> security authorization and acls</a>. Note that this configuration is ignored" +
+            " see <a href=\"https://kafka.apache.org/documentation/#security_authz\"> security authorization and acls</a>. Note that this configuration is ignored" +
             " if an extension of KafkaPrincipalBuilder is provided by the <code>" + PRINCIPAL_BUILDER_CLASS_CONFIG + "</code>" +
             " configuration.";
 
@@ -65,7 +65,7 @@ public class BrokerSecurityConfigs {
             "names to short names (typically operating system usernames). The rules are evaluated in order and the " +
             "first rule that matches a principal name is used to map it to a short name. Any later rules in the list are " +
             "ignored. By default, principal names of the form <code>{username}/{hostname}@{REALM}</code> are mapped " +
-            "to <code>{username}</code>. For more details on the format please see <a href=\"#security_authz\"> " +
+            "to <code>{username}</code>. For more details on the format please see <a href=\"https://kafka.apache.org/documentation/#security_authz\"> " +
             "security authorization and acls</a>. Note that this configuration is ignored if an extension of " +
             "<code>KafkaPrincipalBuilder</code> is provided by the <code>" + PRINCIPAL_BUILDER_CLASS_CONFIG + "</code> configuration.";