Create snupkg symbols packages

Author: Muximize

Build/build-functions.psm1

@@ -111,6 +111,8 @@ function Start-PackNugets([boolean] $IncludeNanoFramework = $false) {
       --no-build `
       --output $nugetOutDir `
       /p:ContinuousIntegrationBuild=true `
+      /p:IncludeSymbols=true `
+      /p:SymbolPackageFormat=snupkg `
       "$root\$projectPath"
 
     if ($lastexitcode -ne 0) { exit 1 }