modify oracle lexer name

[engchina]

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1. Is this request related to a challenge you're experiencing? Tell me about your story.

The default oracle lexer name is "CHINESE_VGRAM_LEXER" that is not suitable for other languages.
And there are WORLD_LEXER and MULTI_LEXER, compared them, I think WORLD_LEXER is better than MULTI_LEXER.

2. Additional context or comments

Oralce docs about WORLD_LEXER and MULTI_LEXER.

WORLD_LEXER:
https://docs.oracle.com/en/database/oracle/oracle-database/21/ccref/oracle-text-indexing-elements.html#GUID-FA7DB079-3247-49DB-A9F9-067F6281F879

MULTI_LEXER:
https://docs.oracle.com/en/database/oracle/oracle-database/21/ccref/oracle-text-indexing-elements.html#GUID-93B17833-A046-468C-BE5F-2BD09A61935C

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• I am interested in contributing to this feature.