Update README.md

README.md

@@ -27,6 +27,7 @@ This repository contains RFCs and DACIs. Lost?
 - [0042-gocd-succeeds-freight-as-our-cd-solution](text/0042-gocd-succeeds-freight-as-our-cd-solution.md): Plan to replace freight with GoCD
 - [0043-instruction-addr-adjustment](text/0043-instruction-addr-adjustment.md): new StackTrace Protocol field that controls adjustment of the `instruction_addr` for symbolication
 - [0044-heartbeat](text/0044-heartbeat.md): Heartbeat monitoring
+- [0046-ttfd-automatic-transaction-span](text/0046-ttfd-automatic-transaction-span.md): Provide a new `time-to-full-display` span to the automatic UI transactions 
 - [0047-introduce-profile-context](text/0047-introduce-profile-context.md): Add Profile Context
 - [0048-move-replayid-out-of-tags](text/0048-move-replayid-out-of-tags.md): Plan to replace freight with GoCD
 - [0063-sdk-crash-monitoring](text/0063-sdk-crash-monitoring.md): SDK Crash Monitoring