Cap the amount of text copied into the stringbuilder in JsonRpcEventSource.Format#1187

AArnott merged 1 commit intomicrosoft:mainmicrosoft/vs-streamjsonrpc:mainfrom

ToddGrun:dev/toddgrun/CapStringBuilderAllocationSizeInJsonRpcEventSource.FormatToddGrun/vs-streamjsonrpc:dev/toddgrun/CapStringBuilderAllocationSizeInJsonRpcEventSource.FormatCopy head branch name to clipboard