### 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
) {
            return parser.map();
        }
    }
    private static XContentParserConfiguration parserConfig(NamedXContentRegistry xContentRegistry) {
        return XContentParserConfiguration.EMPTY.withRegistry(xContentRegistry).withDeprecationHandler(LoggingDeprecationHandler.INSTANCE);
    }
    /**
     * Update local mapping by applying the incoming mapping that have already been merged with the current one on the master
     */
    public void updateMapping(final IndexMetadata currentIndexMetadata, final IndexMetadata newIndexMetadata) {
        assert newIndexMetadata.getIndex().equals(index())
            : "index mismatch: expected " + index() + " but was " + newIndexMetadata.getIndex();
        if (currentIndexMetadata != null && currentIndexMetadata.getMappingVersion() == newIndexMetadata.getMappingVersion()) {
            assert assertNoUpdateRequired(newIndexMetadata);
            return;
        }
        MappingMetadata newMappingMetadata = newIndexMetadata.mapping();
        if (newMappingMetadata != null) {
            String type = newMappingMetadata.type();
            CompressedXContent incomingMappingSource = newMappingMetadata.source();
            Mapping incomingMapping = parseMapping(type, incomingMappingSource);
            DocumentMapper previousMapper;
            synchronized (this) {
                previousMapper = this.mapper;
                assert assertRefreshIsNotNeeded(previousMapper, type, incomingMapping);
                this.mapper = newDocumentMapper(incomingMapping, MergeReason.MAPPING_RECOVERY, incomingMappingSource);
            }
            String op = previousMapper != null ? "updated" : "added";
            if (logger.isDebugEnabled() && incomingMappingSource.compressed().length < 512) {