Merge branch 'jc/orphan-unborn' into maint-2.43

Doc updates to clarify what an "unborn branch" means.

* jc/orphan-unborn:
  orphan/unborn: fix use of 'orphan' in end-user facing messages
  orphan/unborn: add to the glossary and use them consistently

diff --cc Documentation/glossary-content.txt
Simple merge

diff --cc builtin/checkout.c
Simple merge

diff --cc builtin/worktree.c
Simple merge

diff --cc t/t2400-worktree-add.sh
index 245656b53a9702566c33043b7965ece1d8662add,cbad2bd22b7c16bb004b4aae85345e9fa222d38e..4b7627e8529a5b5fd33fe5344108cee83ee22a80
--- 1/t/t2400-worktree-add.sh
--- 2/t/t2400-worktree-add.sh
+++ b/t/t2400-worktree-add.sh
@@@ -709,9 -709,9 +709,9 @@@ test_expect_success 'git worktree --no-
  test_dwim_orphan () {
        local info_text="No possible source branch, inferring '--orphan'" &&
        local fetch_error_text="fatal: No local or remote refs exist despite at least one remote" &&
-       local orphan_hint="hint: If you meant to create a worktree containing a new orphan branch" &&
+       local orphan_hint="hint: If you meant to create a worktree containing a new unborn branch" &&
        local invalid_ref_regex="^fatal: invalid reference: " &&
 -      local bad_combo_regex="^fatal: '[-a-z]*' and '[-a-z]*' cannot be used together" &&
 +      local bad_combo_regex="^fatal: options '[-a-z]*' and '[-a-z]*' cannot be used together" &&
  
        local git_ns="repo" &&
        local dashc_args="-C $git_ns" &&