fix CRAN 'nosuggests' failures

[achubaty]

══ Failed tests ════════════════════════════════════════════════════════════════
  ── Failure (test-Plots.R:83:7): Plots function 1 ───────────────────────────────
  any(grepl("qs", files) & !grepl("gg", files)) is not TRUE
  
  `actual`:   FALSE
  `expected`: TRUE 
  ── Failure (test-Plots.R:83:7): Plots function 1 ───────────────────────────────
  any(grepl("qs", files) & !grepl("gg", files)) is not TRUE
  
  `actual`:   FALSE
  `expected`: TRUE 
  ── Failure (test-Plots.R:83:7): Plots function 1 ───────────────────────────────
  any(grepl("qs", files) & !grepl("gg", files)) is not TRUE
  
  `actual`:   FALSE
  `expected`: TRUE 
  
  [ FAIL 3 | WARN 26 | SKIP 38 | PASS 406 ]
  Error: Test failures
  Execution halted
* checking for unstated dependencies in vignettes ... OK
* checking package vignettes in ‘inst/doc’ ... OK
* checking re-building of vignette outputs ... OK
* checking PDF version of manual ... OK
* checking for non-standard things in the check directory ... OK
* checking for detritus in the temp directory ... OK
* DONE

Status: 1 ERROR, 2 NOTEs