Add clarification

G - [goes to last line](https://vimhelp.org/motion.txt.html#G)

vim-sample/README.md

@@ -41,7 +41,7 @@ Motions:
 * `j` - down by `n` lines
 * `k` - up by `n` lines
 * `l` - right
-* `G` - go to line
+* `G` - go to last line
 * `gg` - go to first line
 * `g0` - go to start of screen line
 * `g^` - go to first non whitespace character of screen line