vim-patch:9.0.0795: readblob() always reads the whole file

Problem:    readblob() always reads the whole file.
Solution:   Add arguments to read part of the file. (Ken Takata,
            closes vim/vim#11402)

11df3aeee5

Remove trailing whitespace in test as done in patch 9.0.1257.
Move the help for rand() before range().

Co-authored-by: K.Takata <kentkt@csc.jp>

src/nvim/eval.lua

@@ -296,7 +296,7 @@ return {
     perleval={args=1, base=1},
     rand={args={0, 1}, base=1},
     range={args={1, 3}, base=1},
-    readblob={args=1, base=1},
+    readblob={args={1, 3}, base=1},
     readdir={args={1, 2}, base=1},
     readfile={args={1, 3}, base=1},
     reduce={args={2, 3}, base=1},