Section 7.4.4 Execution environments: clarify by using, say, h(5) instead of h(1)

[HenrikBengtsson]

In Section 7.4.4 Execution environments, there's:

adv-r/Environments.Rmd

Lines 656 to 663 in dc49c38

	```{r}
	h <- function(x) {
	# 1.
	a <- 2 # 2.
	x + a
	}
	y <- h(1) # 3.
	```

Here there are several uses of 1, 2, and 3 in different roles, e.g. the value of x, the value of a, and y, while also being used as labels for steps 1, 2, and 3 both in the code and in the graphs. This can complicate the parsing of the code and the graphs.

My suggestion is to initiate x with another value, to avoid clashing with the step labels, e.g.

h <- function(x) {
  # 1.
  a <- 4 # 2.
  x + a
}
y <- h(5) # 3.

would change the graph enough so that the binding values are x = 5, a = 4, and y = 9.