ReleaseProcessOverview.md: add gen_script_man_pages.sh to the macOS
bash 4.x+ compatibility note.
Hit for real during SDP 2026.1 GA release Step 13: running it under
macOS's stuck-at-3.2 system bash produced "line 15: ${Version^^}:
bad substitution" -- non-fatal (script still completed and
submitted correctly), but the script wasn't yet listed among the
known bash-4-requiring scripts in this doc's "Preparation" section.