standard.mk: help's fixed-width column runs long target names into their descriptions

[hunterdsp]

Found while auditing doppler's targets — routing local/CI/release through make (doppler-dsp/doppler#602), the same exercise that produced #15. This one is standard.mk's help formatter, not repo config.

The problem

make help collides the target name with its description whenever a name reaches the column width:

  test-examples-python Run the Python example gate (requires pyext)
  test-example-downstream Build the downstream jm example (C only)
  check-docstring-coverage Report docstring coverage across both Python faces
  test-example-downstream-python Build + test the downstream example (Python)

One space separates test-example-downstream (23 chars) from its description — it reads as a single run-on line.

Root cause

help pads to a fixed width:

printf '  %-20s %s\n' "$$t" "$$d"

Any target name ≥ 20 chars overflows the field, leaving only the single literal space between %-20s and %s. 20 is fine for the standard set, but a repo's LOCAL_TARGETS routinely exceed it (doppler has test-example-downstream-python, 30 chars).

Proposal

Auto-size the column to the longest target name, so it can never overflow regardless of a repo's local targets:

@w=0; for t in $(ALL_TARGETS); do [ $${#t} -gt $$w ] && w=$${#t}; done; \
 for t in $(ALL_TARGETS); do \
     $(_STD_DESC); \
     printf '  %-*s  %s\n' "$$w" "$$t" "$$d"; \
 done

%-*s takes the width from its argument; two-space gap after. POSIX sh ($${#t} is portable). No change for repos whose names already fit; long-named repos stop wrapping.

Note this is an org-wide bump: every repo re-vendors standard.mk (its standard-check diffs the vendored copy against the live URL) on next touch. Happy to open the PR.