improve handling of indented R chunks
improve handling of indented R chunks

JanMarvin/rstudio,JanMarvin/rstudio,jar1karp/rstudio,JanMarvin/rstudio,JanMarvin/rstudio,JanMarvin/rstudio,jrnold/rstudio,jar1karp/rstudio,jar1karp/rstudio,jar1karp/rstudio,jar1karp/rstudio,jrnold/rstudio,jrnold/rstudio,jrnold/rstudio,JanMarvin/rstudio,jrnold/rstudio,jar1karp/rstudio,jrnold/rstudio,jar1karp/rstudio,jrnold/rstudio,jrnold/rstudio,jar1karp/rstudio,JanMarvin/rstudio,jar1karp/rstudio,JanMarvin/rstudio,jrnold/rstudio,JanMarvin/rstudio