use 'git diff' rather than 'git show' when showing diff (#7913)
use 'git diff' rather than 'git show' when showing diff (#7913)


JanMarvin/rstudio,JanMarvin/rstudio,JanMarvin/rstudio,JanMarvin/rstudio,JanMarvin/rstudio,JanMarvin/rstudio,JanMarvin/rstudio,JanMarvin/rstudio,JanMarvin/rstudio