Small changes

[vincentvanhees]

1. Fixes Missing declaration of loaded object in g.part5 causes NOTE in package check #1208 by adding declaration of object.
2. Reverses threshold changes in 3.1-3 relating to Non-wear detection in the middle of the SPT window #1172
3. Update read.myacc.csv documentation:
   • No longer refer to the arguments rmc.desiredtz and rmc.configtz that will be deprecated.
   • Emphasize that user should always test their arguments with read.myacc.csv directly, following experience with Discrepancy in MVPA between different input methods #1178

Checklist before merging:

• Existing tests still work (check by running the test suite, e.g. from RStudio).
• Added tests (if you added functionality) or fixed existing test (if you fixed a bug).
• Clean code has been attempted, e.g. intuitive object names and no code redundancy.
• Documentation updated:
  • Function documentation
  • Chapter vignettes for GitHub IO
  • Vignettes for CRAN
• Corresponding issue tagged in PR message. If no issue exist, please create an issue and tag it.
• Updated release notes in inst/NEWS.Rd with a user-readable summary. Please, include references to relevant issues or PR discussions.
• Added your name to the contributors lists in the DESCRIPTION file, if you think you made a significant contribution.
• GGIR parameters were added/removed. If yes, please also complete checklist below.