[R] Upgraded to 4.1.1 assignment operator keys not working

[Rich Shepard]

Just upgraded to R-4.1.1-x86_64-1_SBo on Slackware-14.2/x86_64. While it's
been a while since I last ran R trying 'Alt + -' to enter the assignment
monitor is not working. Assuming the problem is with me I'm not finding what
I'm doing incorrectly in all the docs I searched and I'm suitably
embarrassed that I need to ask for help. But, ... help.

Rich