Add commands to facilitate Spack/Python/OS reporting (#15834)

* Add --version arg to spack python command
* Add `spack debug report` command

share/spack/spack-completion.bash

@@ -655,7 +655,7 @@ _spack_debug() {
     then
         SPACK_COMPREPLY="-h --help"
     else
-        SPACK_COMPREPLY="create-db-tarball"
+        SPACK_COMPREPLY="create-db-tarball report"
     fi
 }
 
@@ -663,6 +663,10 @@ _spack_debug_create_db_tarball() {
     SPACK_COMPREPLY="-h --help"
 }
 
+_spack_debug_report() {
+    SPACK_COMPREPLY="-h --help"
+}
+
 _spack_dependencies() {
     if $list_options
     then
@@ -1272,7 +1276,7 @@ _spack_pydoc() {
 _spack_python() {
     if $list_options
     then
-        SPACK_COMPREPLY="-h --help -c -m"
+        SPACK_COMPREPLY="-h --help -V --version -c -m"
     else
         SPACK_COMPREPLY=""
     fi