better names in coverage report

Give the `cov$functions` columns more informative names, for interactive development. E.g.:

> cov$functions
 [1] "Range@properties$length$getter"
 [2] "Range@properties$length$setter"
 [3] "Range@properties$length$setter"
 [4] "Range@constructor"
 [5] "Range@validator"
 [6] "Range@validator"
 [7] "Range@validator"
 [8] "Range@validator"
 [9] "Range@validator"
[10] "Range@validator"
[11] "method(inside, TestS7::Range)"

R/S7.R

@@ -19,6 +19,7 @@ traverse_S7_generic <- function(x) {
         # Recurse for nested environments
         get_replacements(target_value)
       } else {
+        name <- as.character(attr(target_value, "name", TRUE) %||% name)
         list(replacement(name, env, target_value))
       }
     })
@@ -28,20 +29,24 @@ traverse_S7_generic <- function(x) {
 }
 
 traverse_S7_class <- function(x) {
+  class_name <- S7::prop(x, "name")
   prop_fun_replacements <-
     lapply(S7::prop(x, "properties"), function(p) {
       lapply(c("getter", "setter", "validator"), function(prop_fun) {
         if (!is.null(p[[prop_fun]])) {
-          replacement(prop_fun, env = p, target_value = p[[prop_fun]])
+          replacement(
+            sprintf("%s@properties$%s$%s", class_name, p$name, prop_fun),
+            env = p,
+            target_value = p[[prop_fun]])
         }
       })
   })
   prop_fun_replacements <- unlist(prop_fun_replacements, FALSE, FALSE)
 
   c(
     list(
-      replacement("constructor", env = x, target_value = S7::prop(x, "constructor")),
-      replacement("validator"  , env = x, target_value = S7::prop(x, "validator"))
+      replacement(paste0(class_name, "@constructor"), env = x, target_value = S7::prop(x, "constructor")),
+      replacement(paste0(class_name, "@validator")  , env = x, target_value = S7::prop(x, "validator"))
     ),
     prop_fun_replacements
   )