Docs - fix incorrect reference to '-e' being equivalent to '--export'.

It's short for '--error'.

Bug 11393.

doc/man/man1/sbatch.1

-.TH sbatch "1" "Slurm Commands" "February 2021" "Slurm Commands"
+.TH sbatch "1" "Slurm Commands" "April 2021" "Slurm Commands"
 
 .SH "NAME"
 sbatch \- Submit a batch script to Slurm.
@@ -2215,7 +2215,7 @@ See \fB\-m, \-\-distribution\fR.
 Same as \fB\-m, \-\-distribution\fR
 .TP
 \fBSLURM_EXPORT_ENV\fR
-Same as \fB\-e, \-\-export\fR.
+Same as \fB\-\-export\fR.
 .TP
 \fBSLURM_GPUS\fR
 Number of GPUs requested.