### Description

I was just looking at some Elasticsearch that had lots of "Improve "reloading search analyzers" logs coming from `MapperService` at the INFO level. In my particular case, it was being emitted because analyzers are reloaded as part of doing a recovery. This log is not really helpful as-is, I think we need to do the following:
 - Switch the level to DEBUG, it's not important enough to warrant an INFO log.
 - Add which index reloaded its search analyzers to the log.

What do you think?
server/src/main/java/org/elasticsearch/index/mapper/MapperService.java
}
    public boolean hasNested() {
        return mappingLookup().nestedLookup() != NestedLookup.EMPTY;
    }
    public IndexAnalyzers getIndexAnalyzers() {
        return this.indexAnalyzers;
    }
    public MappingParserContext parserContext() {
        return mappingParserContextSupplier.get();
    }
    /**
     * Exposes a {@link DocumentParser}
     * @return a document parser to be used to parse incoming documents
     */
    public DocumentParser documentParser() {
        return this.documentParser;
    }
    Map<Class<? extends MetadataFieldMapper>, MetadataFieldMapper> getMetadataMappers() {
        final MappingParserContext mappingParserContext = parserContext();
        final DocumentMapper existingMapper = mapper;
        final Map<String, MetadataFieldMapper.TypeParser> metadataMapperParsers = mapperRegistry.getMetadataMapperParsers(
            indexSettings.getIndexVersionCreated()
        );
        Map<Class<? extends MetadataFieldMapper>, MetadataFieldMapper> metadataMappers = new LinkedHashMap<>();
        if (existingMapper == null) {
            for (MetadataFieldMapper.TypeParser parser : metadataMapperParsers.values()) {
                MetadataFieldMapper metadataFieldMapper = parser.getDefault(mappingParserContext);