fix typos; update spelling list; clean up

Author: bcumming

.github/actions/spelling/allow.txt

@@ -4,6 +4,7 @@ AMD
 Alpstein
 Balfrin
 Besard
+Besso
 Broyden
 CFLAGS
 CHARMM
@@ -120,6 +121,7 @@ artifactory
 autodetection
 aws
 baremetal
+besso
 biomolecular
 blaspp
 blt

docs/alps/clusters.md

@@ -48,7 +48,7 @@ The following clusters are part of the platforms that are fully operated by CSCS
 <div class="grid cards" markdown>
 -   :fontawesome-solid-mountain: __Porting and Development__
 
-    Besso is a small system for selected customers to do code portina and development with AMD and NVIDIA GPUs.
+    Besso is a small system used by some partners for development and porting with AMD and NVIDIA GPUs.
 
     [:octicons-arrow-right-24: Besso][ref-cluster-besso]
 </div>

docs/clusters/besso.md

@@ -32,17 +32,9 @@ To connect to Besso via SSH, first refer to the [ssh guide][ref-ssh].
 [](){#ref-cluster-besso-uenv}
 #### uenv
 
-CSCS does not provide officialy supported applications on Besso.
-Basic programming environments are provided for the a100 and mi200 node types.
+Besso is a development and testing system, for which CSCS does not provide supported applications.
 
-<div class="grid cards" markdown>
-
--    :fontawesome-solid-layer-group: __Programming Environments__
-
-    Provide compilers, MPI, Python, common libraries and tools used to build your own applications.
-
-    * [prgenv-gnu][ref-uenv-prgenv-gnu]
-</div>
+Instead, the [prgenv-gnu][ref-uenv-prgenv-gnu] programming environment is provided for the both the [a100][ref-alps-a100-node] and [mi200][ref-alps-mi200-node] node types.
 
 [](){#ref-cluster-besso-containers}
 #### Containers