Merge pull request #552 from cmu-delphi/ds/vignettes3

doc: fix typo in archive vignette

vignettes/epi_archive.Rmd

@@ -365,12 +365,10 @@ dv_archive_faux <- edf_latest %>%
 
 Now we can slide the forecaster over the faux archive to produce forecasts at a
 number of dates in the past, spaced a month apart. Note that we will use the
-`case_rate_7d_av` signal from the merged archive, which is the smoothed COVID-19
-case rate. This is clearly equivalent, up to a constant, to modeling weekly sums
-of COVID-19 cases. We will forecast 7, 14, 21, and 28 days ahead, so to reduce
-typing, we create the wrapper function `k_week_ahead()`. We also produce
-forecasts in a version-aware way, which simply requires us to use the true
-`epi_archive` object instead of the faux one.
+`percent_cli` signal from the merged archive, which is the smoothed COVID-19
+case rate. We will forecast 7, 14, 21, and 28 days ahead. We produce forecasts
+in a version-aware way, which simply requires us to use the true `epi_archive`
+object instead of the faux one.
 
 ```{r}
 # Generate a sequence of forecast dates. Starting 3 months into the data, so we have