Update Javadoc about normalizeEntry in Kuromoji DictionaryBuilder [LUCENE-9270]

[asfimport]

The normalizeEntry option is missing from the Javadoc of Kuromoji DictionaryBuilder. Without this explanation, users don't know what it means until they see the code. Also, if user follows the usage of Javadoc, it will not be built.

So the following contents need to be applied:

1) Change usage before:   java -cp [lucene classpath] org.apache.lucene.analysis.ja.util.DictionaryBuilder \     ${inputDir} ${outputDir} ${encoding} after:   java -cp [lucene classpath] org.apache.lucene.analysis.ja.util.DictionaryBuilder \     ${inputDir} ${outputDir} ${encoding} ${normalizeEntry}

2) Add description about normalizeEntry

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Migrated from LUCENE-9270 by Namgyu Kim (@danmuzi), updated Mar 11 2020

[asfimport]

ASF subversion and git services (migrated from JIRA)

Commit f0a49738ca661564cd5b222d00a316dfb20e41e4 in lucene-solr's branch refs/heads/master from Namgyu Kim https://gitbox.apache.org/repos/asf?p=lucene-solr.git;h=f0a4973

LUCENE-9270: Update Javadoc about normalizeEntry in the Kuromoji DictionaryBuilder

[asfimport]

ASF subversion and git services (migrated from JIRA)

Commit 8bbae8feae7c8656748b82101be61dbc7b6b7fb1 in lucene-solr's branch refs/heads/branch_8x from Namgyu Kim https://gitbox.apache.org/repos/asf?p=lucene-solr.git;h=8bbae8f

LUCENE-9270: Update Javadoc about normalizeEntry in the Kuromoji DictionaryBuilder