### 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
IdFieldMapper idFieldMapper,
        ScriptCompiler scriptCompiler,
        Supplier<DocumentParsingObserver> documentParsingObserverSupplier
    ) {
        this(
            () -> clusterService.state().getMinTransportVersion(),
            indexSettings,
            indexAnalyzers,
            parserConfiguration,
            similarityService,
            mapperRegistry,
            searchExecutionContextSupplier,
            idFieldMapper,
            scriptCompiler,
            documentParsingObserverSupplier
        );
    }
    @SuppressWarnings("this-escape")
    public MapperService(
        Supplier<TransportVersion> clusterTransportVersion,
        IndexSettings indexSettings,
        IndexAnalyzers indexAnalyzers,
        XContentParserConfiguration parserConfiguration,
        SimilarityService similarityService,
        MapperRegistry mapperRegistry,
        Supplier<SearchExecutionContext> searchExecutionContextSupplier,
        IdFieldMapper idFieldMapper,
        ScriptCompiler scriptCompiler,
        Supplier<DocumentParsingObserver> documentParsingObserverSupplier
    ) {