Todos in Chapter 3

[padasch]

• [x] Text says tibble is printed but code chunk does not return tibble https://github.com/geco-bern/agds/blob/d36303134e5cb252e664daf1a37753625a72c177/03-data_wrangling.Rmd#L65
• [x] Variable for half hourly dataframe was renamed but the text still refers to df_hh https://github.com/geco-bern/agds/blob/d36303134e5cb252e664daf1a37753625a72c177/03-data_wrangling.Rmd#L63

[stineb]

Resolved with commit c97adfeec8be5b12b4a1882ac340a49a15a25f00