Typo - Chp 7, Sec 7.5, digits argument for m_rsq not valid

[staceyhancock]

• Chapter number: 7

• Section number: 7.5

• Other location identifier, if any (e.g., figure number, table number, footnote number, etc.): Exercise 23c. (Poverty and unemployment)

• Original text: Line 506 of 07-ex-model-slr.Rmd was throwing an error when building the book due to the option "digits = 0". I'm not sure if you had the same error, so if not, there's no issue to resolve.

• Suggestion for corrected text: I changed the option to "digits = 0" on line 506: m_rsq <- format(round(glance(m)$r.squared, 2)*100, digits = 1). That fixed the compilation error, and the displayed value (46%) is still the same.

• Justification for suggestion: bs4_book wouldn't build with "digits = 0" as the option.