Update the R functions to allow outputting spending time

[LittleBeannie]

• Update gs_design_ahr to output spending time
• Update summary with a new argument display_spending_time to allow outputting spending time or not (default is FALSE)
• Update as_gt

[jdblischak]

I tested this locally. Overall looking good! To start I have some minor comments on how to organize the R code

[jdblischak]

The macOS build failed during the setup due to a known temporary problem (yihui/litedown#112). I restarted the build.

[jdblischak]

The Ubuntu build with R-devel failed to build the vignette gsDesign2.Rmd:

* creating vignettes ... ERROR
Error: --- re-building ‘gsDesign2.Rmd’ using rmarkdown
Quitting from gsDesign2.Rmd:123-133 [unnamed-chunk-5]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<error/rlang_error>
Error in `[.data.table`:
! attempt access index 6/6 in VECTOR_ELT
---
Backtrace:
    ▆
 1. └─gsDesign2::fixed_design_ahr(...)
 2.   └─gsDesign2::gs_design_ahr(...) at gsDesign2/R/fixed_design_ahr.R:114:5
 3.     └─gsDesign2::gs_info_ahr(...) at gsDesign2/R/gs_design_ahr.R:228:3
 4.       ├─dplyr::select(...) at gsDesign2/R/gs_info_ahr.R:126:5
 5.       └─gsDesign2::ahr(...) at gsDesign2/R/gs_info_ahr.R:126:5
 6.         └─gsDesign2::pw_info(...) at gsDesign2/R/ahr.R:108:3
 7.           ├─tbl_event[, `:=`(info0, event * q_c * q_e), by = .(time)] at gsDesign2/R/pw_info.R:170:3
 8.           └─data.table:::`[.data.table`(...) at gsDesign2/R/pw_info.R:170:3
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Error: Error: processing vignette 'gsDesign2.Rmd' failed with diagnostics:
attempt access index 6/6 in VECTOR_ELT
--- failed re-building ‘gsDesign2.Rmd’
SUMMARY: processing the following file failed:
  ‘gsDesign2.Rmd’
Error: Error: Vignette re-building failed.

The line that caused the failure hasn't been updated recently (nor has the surrounding code):

gsDesign2/R/pw_info.R

Line 170 in ae1ed90

tbl_event[, info0 := event * q_c * q_e, by = .(time)]

[jdblischak]

Both the macOS and Ubuntu builds passed on restart