Fix spack install --v[tab] spec (#28278)

share/spack/qa/completion-test.sh

@@ -70,6 +70,16 @@ _test_debug_functions() {
         emulate -L sh
     fi
 
+    # Test whether `spack install --verb[] spec` completes to `spack install --verbose spec`
+    COMP_LINE='spack install --verb spec'
+    COMP_POINT=20
+    COMP_WORDS=(spack install --verb spec)
+    COMP_CWORD=2
+    COMP_KEY=9
+    COMP_TYPE=64
+    _bash_completion_spack
+    contains "--verbose" echo "${COMPREPLY[@]}"
+
     # This is a particularly tricky case that involves the following situation:
     #     `spack -d [] install `
     # Here, [] represents the cursor, which is in the middle of the line.