Document MultipartProperties

Closes gh-2779

spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -102,6 +102,13 @@ content into your application; rather pick only the properties that you need.
 	spring.resources.cache-period= # cache timeouts in headers sent to browser
 	spring.resources.add-mappings=true # if default mappings should be added
 
+	# MULTIPART ({sc-spring-boot-autoconfigure}/web/MultipartProperties.{sc-ext}[MultipartProperties])
+	multipart.enabled=true
+	multipart.file-size-threshold=0 # Threshold after which files will be written to disk.
+	multipart.location= # Intermediate location of uploaded files.
+	multipart.max-file-size=1Mb # Max file size.
+	multipart.max-request-size=10Mb # Max request size.
+
 	# SPRING HATEOAS ({sc-spring-boot-autoconfigure}/hateoas/HateoasProperties.{sc-ext}[HateoasProperties])
 	spring.hateoas.apply-to-primary-object-mapper=true # if the primary mapper should also be configured