Improve `spack find` output in environments (#42334)

This adds some improvements to `spack find` output when in environments based
around some thoughts about what users want to know when they're in an env.

If you're working in an enviroment, you mostly care about:
* What are the roots
* Which ones are installed / not installed
* What's been added that still needs to be concretized

So, this PR adds a couple tweaks to display that information more clearly:

- [x] We now display install status next to every root. You can easily see
      which are installed and which aren't.

- [x] When you run `spack find -l` in an env, the roots now show their concrete
      hash (if they've been concretized). They previously would show `-------`
      (b/c the root spec itself is abstract), but showing the concretized root's
      hash is a lot more useful.

- [x] Newly added/unconcretized specs still show `-------`, which now makes more
      sense, b/c they are not concretized.

- [x] There is a new option, `-r` / `--only-roots` to *only* show env roots if
      you don't want to look at all the installed specs.

- [x] Roots in the installed spec list are now highlighted as bold. This is
      actually an old feature from the first env implementation , but various
      refactors had disabled it inadvertently.

2 files changed, 4 insertions, 2 deletions

diff --git a/share/spack/spack-completion.bash b/share/spack/spack-completion.bash
index 2b2dec2367..09043cec22 100755
--- a/share/spack/spack-completion.bash
+++ b/share/spack/spack-completion.bash
@@ -1197,7 +1197,7 @@ _spack_fetch() {
 _spack_find() {
     if $list_options
     then
-        SPACK_COMPREPLY="-h --help --format -H --hashes --json -d --deps -p --paths --groups --no-groups -l --long -L --very-long -t --tag -N --namespaces -c --show-concretized -f --show-flags --show-full-compiler -x --explicit -X --implicit -u --unknown -m --missing -v --variants --loaded -M --only-missing --deprecated --only-deprecated --install-tree --start-date --end-date"
+        SPACK_COMPREPLY="-h --help --format -H --hashes --json -d --deps -p --paths --groups --no-groups -l --long -L --very-long -t --tag -N --namespaces -r --only-roots -c --show-concretized -f --show-flags --show-full-compiler -x --explicit -X --implicit -u --unknown -m --missing -v --variants --loaded -M --only-missing --deprecated --only-deprecated --install-tree --start-date --end-date"
     else
         _installed_packages
     fi
diff --git a/share/spack/spack-completion.fish b/share/spack/spack-completion.fish
index 24cb8e5040..e4b8689e55 100755
--- a/share/spack/spack-completion.fish
+++ b/share/spack/spack-completion.fish
@@ -1743,7 +1743,7 @@ complete -c spack -n '__fish_spack_using_command fetch' -l deprecated -f -a conf
 complete -c spack -n '__fish_spack_using_command fetch' -l deprecated -d 'allow concretizer to select deprecated versions'
 
 # spack find
-set -g __fish_spack_optspecs_spack_find h/help format= H/hashes json d/deps p/paths groups no-groups l/long L/very-long t/tag= N/namespaces c/show-concretized f/show-flags show-full-compiler x/explicit X/implicit u/unknown m/missing v/variants loaded M/only-missing deprecated only-deprecated install-tree= start-date= end-date=
+set -g __fish_spack_optspecs_spack_find h/help format= H/hashes json d/deps p/paths groups no-groups l/long L/very-long t/tag= N/namespaces r/only-roots c/show-concretized f/show-flags show-full-compiler x/explicit X/implicit u/unknown m/missing v/variants loaded M/only-missing deprecated only-deprecated install-tree= start-date= end-date=
 complete -c spack -n '__fish_spack_using_command_pos_remainder 0 find' -f -a '(__fish_spack_installed_specs)'
 complete -c spack -n '__fish_spack_using_command find' -s h -l help -f -a help
 complete -c spack -n '__fish_spack_using_command find' -s h -l help -d 'show this help message and exit'
@@ -1769,6 +1769,8 @@ complete -c spack -n '__fish_spack_using_command find' -s t -l tag -r -f -a tags
 complete -c spack -n '__fish_spack_using_command find' -s t -l tag -r -d 'filter a package query by tag (multiple use allowed)'
 complete -c spack -n '__fish_spack_using_command find' -s N -l namespaces -f -a namespaces
 complete -c spack -n '__fish_spack_using_command find' -s N -l namespaces -d 'show fully qualified package names'
+complete -c spack -n '__fish_spack_using_command find' -s r -l only-roots -f -a only_roots
+complete -c spack -n '__fish_spack_using_command find' -s r -l only-roots -d 'don\'t show full list of installed specs in an environment'
 complete -c spack -n '__fish_spack_using_command find' -s c -l show-concretized -f -a show_concretized
 complete -c spack -n '__fish_spack_using_command find' -s c -l show-concretized -d 'show concretized specs in an environment'
 complete -c spack -n '__fish_spack_using_command find' -s f -l show-flags -f -a show_flags