Replace [] with () in description (#17940)

The tcl module for r-dorng will fail to load due to the [] characters in
the description. This happens for Tcl formatted modules loaded by Lmod
at least.

```
module load r-dorng-1.7.1-gcc-9.2.0-wtq7bne
Lmod has detected the following error: .../spack/share/spack/modules/linux-centos7-broadwell/r-dorng-1.7.1-gcc-9.2.0-wtq7bne:(r-dorng-1.7.1-gcc-9.2.0-wtq7bne):
invalid command name "L'Ecuyer"
```

Split text for short and long descriptions.

1 files changed, 7 insertions, 5 deletions

diff --git a/var/spack/repos/builtin/packages/r-dorng/package.py b/var/spack/repos/builtin/packages/r-dorng/package.py
index a20cd96356..5c4f0fbc78 100644
--- a/var/spack/repos/builtin/packages/r-dorng/package.py
+++ b/var/spack/repos/builtin/packages/r-dorng/package.py
@@ -9,11 +9,13 @@ from spack import *
 class RDorng(RPackage):
     """Provides functions to perform reproducible parallel foreach loops,
        using independent random streams as generated by L'Ecuyer's combined
-       multiple-recursive generator
-       [L'Ecuyer (1999), <doi:10.1287/opre.47.1.159>]. It enables to easily
-       convert standard %dopar% loops into fully reproducible loops,
-       independently of the number of workers, the task scheduling strategy,
-       or the chosen parallel environment and associated foreach backend."""
+       multiple-recursive generator (L'Ecuyer (1999),
+       <doi:10.1287/opre.47.1.159>).
+
+       It enables to easily convert standard %dopar% loops into fully
+       reproducible loops, independently of the number of workers, the task
+       scheduling strategy, or the chosen parallel environment and associated
+       foreach backend."""
 
     homepage = "https://cloud.r-project.org/package=doRNG"
     url      = "https://cloud.r-project.org/src/contrib/doRNG_1.6.6.tar.gz"