Fix typo (#1497)

missing-values.qmd

@@ -72,7 +72,7 @@ Sometimes you'll hit the opposite problem where some concrete value actually rep
 This typically arises in data generated by older software that doesn't have a proper way to represent missing values, so it must instead use some special value like 99 or -999.
 
 If possible, handle this when reading in the data, for example, by using the `na` argument to `readr::read_csv()`, e.g., `read_csv(path, na = "99")`.
-If you discover the problem later, or your data source doesn't provide a way to handle on it read, you can use `dplyr::na_if()`:
+If you discover the problem later, or your data source doesn't provide a way to handle it on read, you can use `dplyr::na_if()`:
 
 ```{r}
 x <- c(1, 4, 5, 7, -99)