Fix serializable bug when using plugins during pdf generation (#2210)
Fix serializable bug when using plugins during pdf generation (#2210)


dotnet/docfx,pascalberger/docfx,pascalberger/docfx,pascalberger/docfx,superyyrrzz/docfx,superyyrrzz/docfx,dotnet/docfx,superyyrrzz/docfx,dotnet/docfx