[ESS] ESS does not find R

[Stephen Bond]

Hello,

I have built an older version of R without running `make install` as I
am not sure if it is satisfactory and cleaning up is not easy for me.
I have 
```
~$ which R
/home/stephen/Downloads/R-4.3.3/bin/R
```
and typing `R` in a terminal works fine. ESS cannot find it. I tried
all of these:
```
(setq ess-directory-containing-R "/home/stepheen/Downloads") 
(setq ess-directory-containing-R "/home/stepheen/Downloads/R-4.3.3") 
(setq ess-directory-containing-R "/home/stepheen/Downloads/R-
4.3.3/bin") 
```
and nothing works. I set the inferior-ess-r-program to "R" (default was
nil) and still nothing. very very strange.

Thanks everybody.
Stephen