Fix xmldoc build errors

[MaceWindu]

[19-05-25 01:47:31.608]Warning:[BuildCommand.BuildCore.Build Document.LinkPhaseHandlerWithIncremental.Apply Templates](api/LinqToDB.Data.BulkCopyOptions.yml)The value of property 'name' in uid 'MaxBatchSize' is not string
[19-05-25 01:47:31.611]Warning:[BuildCommand.BuildCore.Build Document.LinkPhaseHandlerWithIncremental.Apply Templates](api/LinqToDB.EntityFrameworkCore.LinqToDBForEFToolsImplDefault.yml)The value of property 'name' in uid 'LinqToDB.EntityFrameworkCore.EFCoreMetadataReader' is not string
[19-05-25 01:47:31.616]Warning:[BuildCommand.BuildCore.Build Document.LinkPhaseHandlerWithIncremental.Apply Templates](api/LinqToDB.Common.Configuration.Linq.yml)The value of property 'name' in uid 'LinqToDB.Linq.Query`1.ClearCache' is not string
[19-05-25 01:47:31.617]Warning:[BuildCommand.BuildCore.Build Document.LinkPhaseHandlerWithIncremental.Apply Templates](api/LinqToDB.Mapping.MappingSchema.yml)The value of property 'name' in uid 'System.Data.Linq.Mapping' is not string
[19-05-25 01:47:31.617]Warning:[BuildCommand.BuildCore.Build Document.LinkPhaseHandlerWithIncremental.Apply Templates](api/LinqToDB.Mapping.MappingSchema.yml)The value of property 'name' in uid 'Microsoft.SqlServer.Server' is not string