Merge branch 'add-user-error-message-for-missing-strata' of https://g…

…ithub.com/UCD-SERG/serocalculator into add-user-error-message-for-missing-strata

vignettes/methodology.qmd

@@ -339,7 +339,10 @@ $$
 
 ::: notes
 
-The derivative of this expression doesn't come out cleanly, so we will use a *numerical method* (specifically, a Newton-type algorithm, implemented by `stats::nlm()`) to find the MLE and corresponding standard error.
+The derivative of this expression doesn't come out cleanly, 
+so we will use a *numerical method* 
+(specifically, a Newton-type algorithm, implemented by `stats::nlm()`) 
+to find the MLE and corresponding standard error.
 
 :::