Fix pepper diagram (#1499)

Update caption and remove duplicated sentence

base-R.qmd

@@ -338,7 +338,6 @@ l <- list(
 The difference between `[` and `[[` is particularly important for lists because `[[` drills down into the list while `[` returns a new, smaller list.
 To help you remember the difference, take a look at the unusual pepper shaker shown in @fig-pepper.
 If this pepper shaker is your list `pepper`, then, `pepper[1]` is a pepper shaker containing a single pepper packet.
-If we suppose this pepper shaker is a list called `pepper`, then `pepper[1]` is a pepper shaker containing a single pepper packet.
 `pepper[2]` would look the same, but would contain the second packet.
 `pepper[1:2]` would be a pepper shaker containing two pepper packets.
 `pepper[[1]]` would extract the pepper packet itself.
@@ -349,8 +348,8 @@ If we suppose this pepper shaker is a list called `pepper`, then `pepper[1]` is
 #| out-width: "100%"
 #| fig-cap: >
 #|   (Left) A pepper shaker that Hadley once found in his hotel room.
-#|   (Middle) `pepper[[1]]`.
-#|   (Right) `pepper[[1]][[1]]`
+#|   (Middle) `pepper[1]`.
+#|   (Right) `pepper[[1]]`
 #| fig-alt: >
 #|   Three photos. On the left is a photo of a glass pepper shaker. Instead of 
 #|   the pepper shaker containing pepper, it contains a single packet of pepper.