shell: support more mustache tags #10044

Job	Run time
validate commits	10s
python linting	31s
Generate build matrix	8s
spelling	5s
bookworm - test-install	12m 34s
bookworm - 32 bit	13m 2s
noble - test-install	12m 51s
el9 - test-install	12m 41s
alpine - test-install	12m 28s
fedora40 - test-install	11m 52s
jammy - test-install	12m 4s
focal - py3.8	16m 54s
bookworm - gcc-12,content-s3,distcheck	20m 3s
fedora40 - clang-18	16m 39s
coverage	23m 58s
el8 - ascii	19m 20s
el8 - test-install	13m 28s
el8 - system,coverage	7m 17s
inception	22m 45s
flux-accounting check	4m 35s
flux-pam check	4m 15s
flux-pmix check	13m 21s
macos build only	3m 35s
flux-sched check	6m 53s
Generate docker manifest	1s
	4h 21m 30s

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