Fix the name of Albert H. Munsell (#3947)

Author: yutannihilation

vignettes/ggplot2-specs.Rmd

@@ -32,7 +32,7 @@ Almost every geom has either colour, fill, or both. Colours and fills can be spe
 
 *   The [munsell](https://github.com/cwickham/munsell) package, by Charlotte 
     Wickham, makes it easy to choose specific colours using a system designed by 
-    Alfred Munsell. If you invest a little in learning the system, it provides
+    Albert H. Munsell. If you invest a little in learning the system, it provides
     a convenient way of specifying aesthetically pleasing colours.
 
     ```{r}