gh-38294: Filter out R warnings
These are causing some doctest failures after
https://github.com/sagemath/sage/pull/35396
```
**********************************************************************
File "/usr/lib/python3.12/site-packages/sage/interfaces/r.py", line 51,
in sage.interfaces.r
Failed example:
v = 2*x+y+1; v
Expected:
[1] 32.2 17.8 10.3 20.2 66.1 21.8 22.6 12.8 16.9 50.8 43.5
Got:
R[write to console]: Además:
R[write to console]: Aviso:
<BLANKLINE>
R[write to console]: In sage10 + sage6 :
R[write to console]:
<BLANKLINE>
R[write to console]: longitud de objeto mayor no es múltiplo de la
longitud de uno menor
<BLANKLINE>
[1] 32.2 17.8 10.3 20.2 66.1 21.8 22.6 12.8 16.9 50.8 43.5
**********************************************************************
File "/usr/lib/python3.12/site-packages/sage/interfaces/r.py", line 78,
in sage.interfaces.r
Failed example:
r(-17).sqrt()
Expected:
[1] NaN
Got:
R[write to console]: Además:
R[write to console]: Aviso:
<BLANKLINE>
R[write to console]: In sqrt(sage10) :
R[write to console]: Se han producido NaNs
<BLANKLINE>
[1] NaN
**********************************************************************
File "/usr/lib/python3.12/site-packages/sage/interfaces/r.py", line 356,
in sage.interfaces.r._setup_r_to_sage_converter
Failed example:
r(-17).sqrt().sage()
Expected:
nan
Got:
R[write to console]: Además:
R[write to console]: Aviso:
<BLANKLINE>
R[write to console]: In sqrt(sage4) :
R[write to console]: Se han producido NaNs
<BLANKLINE>
nan
**********************************************************************
```
URL: https://github.com/sagemath/sage/pull/38294
Reported by: Antonio Rojas
Reviewer(s): Matthias Köppe
