Minor fixes identified through shellcheck and other tools (#350)

* fix whitespace

* fix spelling

* fix whitespace

* unify headers of tests

* fix some issues in tests, identified by shellcheck

* fix bash completions

bash completion files are not supposed to be executable

* fix some issues identified by shellcheck

Co-authored-by: Ali Karbassi <ali@karbassi.com>

tests/actions-test-lib.sh

@@ -21,7 +21,7 @@ make_action_in_folder()
 {
     unset TODO_ACTIONS_DIR
     [ -d .todo.actions.d ] || mkdir .todo.actions.d
-    mkdir .todo.actions.d/$1
+    mkdir ".todo.actions.d/$1"
     cat > ".todo.actions.d/$1/$1" <<EOF
 #!/bin/bash
 [ "\$1" = "usage" ] && {