calendar: pull March's sanctoral calendar (pre-1955 pull, 3/12)

7 saints for March, all winning outright on a clean per-annum date. Notably
St. Benedict himself (Mar 21, Duplex I. classis, the founder — "S. P. N."
in the source) turns out to have no unique Oratio/Antiphon at all in this
date's source file, only Common-of-an-Abbot cross-references — flagged in
his own file to check his second (July) feast when that month comes up.

Two Benedictine-oblate saints (Frances of Rome, Gregory the Great) are
marked "O. N." (Ordinis Nostri) in the source — real significance for a
monastic calendar. St. Frances also needed a new common category,
common-of-a-widow (she's neither virgin nor martyr).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/data/calendar/saints/forty-holy-martyrs.yml

@@ -0,0 +1,8 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2033-03-10, no Sunday collision) -- winner outright, Semiduplex.
+# Own proper collect, no unique antiphon of their own.
+id: forty-holy-martyrs
+name: "The Forty Holy Martyrs"
+rank: semiduplex
+common: common-of-several-martyrs
+propers: "forty-holy-martyrs"