Update vignettes/epidatr.Rmd

Author: dshemetov

vignettes/epidatr.Rmd

@@ -88,7 +88,7 @@ epidata$signals$`fb-survey:smoothed_cli`
 ```
 
 These objects can be used directly to fetch data, without requiring us to use
-the `covidcast()` function. Simple use the `$call` attribute of the object:
+the `covidcast()` function. Simply use the `$call` attribute of the object:
 
 ```{r}
 epicall <- epidata$signals$`fb-survey:smoothed_cli`$call("state", "pa", epirange(20210405, 20210410))