Add April Matins readings for SanctiM-track saints

All 9 of April's SanctiM-track saints authored. Found a new wrinkle:
St. Catherine of Siena and St. Peter Martyr sit on swapped dates
between this app's calendar and the general Tridentine one (Apr 29/30
each way), not just an off-by-a-few-days shift like earlier cases.
Also hit a reference-engine data bug on St. George (English prose
filed under a Latin heading) and another genuinely Monastic-only saint
(St. Robert of Molesme) needing an original translation.

src/data/propers/nocturn-readings/st-leo-i.yml

@@ -0,0 +1,84 @@
+# Matins Nocturn 2 reading for St. Leo I ("the Great"), Pope, Confessor,
+# Doctor (Apr 11) — SanctiM/04-11.txt inherits the whole day
+# (`@Sancti/04-11`) with no Nocturn 2/3 override, so this saint's own
+# vita is sourced from the Tridentine track exactly as for a pre-1955
+# saint (see memory vu-matins-pre1955-saints, vu-matins-sanctim-saints).
+# web/www/horas/Latin/Sancti/04-11.txt, English/Sancti/04-11.txt.
+# Lectio4-6 combined into one reading, one continuous vita, no genuine
+# source break. No responsory given in the source.
+id: st-leo-i
+readings:
+  - nocturn: 2
+    isGospel: false
+    text:
+      la: >-
+        Leo primus, Etruscus, eo tempore præfuit Ecclesiæ, cum rex Hunnorum Attila, cognomento
+        Flagellum Dei, in Italiam invadens, Aquilejam triennii obsidione captam diripuit et
+        incendit. Unde cum Romam ardenti furore raperetur, jamque copias, ubi Mincius in Padum
+        influit, trajicere pararet, occurrit ei Leo, malorum Italiæ impendentium misericordia
+        permotus: cujus divina eloquentia persuasum est Attilæ, ut regrederetur. Qui interrogatus
+        a suis, quid esset quod præter consuetudinem tam humiliter Romani Pontificis imperata
+        faceret; respondit, se astantem quemdam alium, illo loquente, sacerdotali habitu veritum
+        esse, sibi stricto gladio minitantem mortem, nisi Leoni obtemperaret. Quare in Pannoniam
+        reversus est.
+
+
+        Leo autem Romæ singulari omnium lætitia exceptus, paulo post invadenti Urbem Genserico,
+        eadem eloquentiæ vi et sanctitatis opinione persuasit, ut ab incendio, ignominiis, ac
+        cædibus abstineret. Sed cum Ecclesiam a multis hæresibus oppugnari, maximeque a
+        Nestorianis et Eutychianis exagitari videret; ad eam purgandam, et in fide catholica
+        confirmandam, concilium Chalcedonense indixit, ubi sexcentis triginta coactis episcopis,
+        Eutyches et Dioscorus, et iterum Nestorius condemnati sunt: ejusdemque concilii decreta
+        sua auctoritate confirmavit.
+
+
+        His actis, sanctus Pontifex se ad reficiendas et ædificandas ecclesias convertit. Cujus
+        suasu Demetria, pia femina, sancti Stephani ecclesiam construxit in suo fundo via
+        Latina, tertio ab Urbe milliario: ipse via Appia sub nomine sancti Cornelii alteram
+        condidit. Multas præterea et sacras ædes, et sacra earum vasa restituit. In tribus
+        basilicis, Petri, Pauli, et Constantiniana, cameras exstruxit: ædificavit monasterium
+        vicinum basilicæ sancti Petri: sepulcris Apostolorum custodes adhibuit, quos cubicularios
+        appellavit. Statuit, ut in actione mysterii diceretur: Sanctum sacrificium, immaculatam
+        hostiam. Sanxit, ne monacha benedictum capitis velamen reciperet, nisi quadraginta
+        annorum virginitatem probasset. His et aliis præclare gestis, cum multa sancte et
+        luculenter scripsisset, quarto Idus Novembris obdormivit in Domino. Sedit in pontificatu
+        annos viginti unum, mensem unum, dies tredecim.
+      en: >-
+        Leo was an Etruscan who ruled the Church at the time when Attila, king of the Huns, whose
+        surname is the Scourge of God, invaded Italy, and after a siege of three years, took,
+        sacked, and burnt Aquileia. Thence he was hurrying to Rome, on fire with anger, and his
+        troops were already preparing to cross the Po, at the place where that river is joined by
+        the Mincio, when he was met by Leo, moved with compassion at the thought of the ruin which
+        hung over Italy. By his God-given eloquence, Attila was persuaded to turn back, and when he
+        was afterwards asked by his servants why, contrary to his custom, he had so meekly yielded
+        to the entreaties of the Bishop of Rome, he answered that he had been alarmed by a figure
+        dressed like a Priest, which had appeared at the side of Leo while he was speaking, holding
+        a drawn sword, and had made as though to kill the king unless he consented. And so he
+        returned into Pannonia.
+
+
+        Leo went back to Rome, where he was received with rejoicing by all men. A while later,
+        Genseric entered the city, but Leo, by the power of his eloquence and the authority of his
+        holy life, persuaded him to abstain from fire, insult, and slaughter. When Leo beheld how
+        the Church was assailed by many heresies, and in dire trouble through the Nestorians and
+        Eutychians, to purify the same and establish her in the Catholic Faith, he called the
+        Council of Chalcedon, where, in an assembly of six hundred and thirty Bishops, Nestorius
+        was again condemned, along with Eutyches and Dioscorus; the decrees of which Council were
+        confirmed by the authority of Leo.
+
+
+        After these matters, this holy Pope set himself to the restoration and building of
+        Churches. By his advice that godly woman Demetria built the Church of St. Stephen upon
+        her farm on the Latin Road, at the third milestone from the city. He himself built another
+        Church upon the Appian Way, which Church is called that of St. Cornelius. He restored
+        likewise many other Churches, and the holy vessels used therein. He built Clergy-houses at
+        the three Basilicas of Peter, Paul, and Constantine. He built a monastery hard by the
+        Basilica of St. Peter. He appointed for the graves of the Apostles certain keepers, whom
+        he called the Chamberlains of the said Apostles. He ordained that in the action of the
+        Mystery should be uttered the words An holy sacrifice, an offering without spot. He
+        ordered that no nun should have the covering of her head blessed until she had made trial
+        of her virginity for forty years. After doing all these and other illustrious works, and
+        after he had written much that is both godly and easy to be understood, he fell asleep in
+        the Lord on the eleventh day of April. He held the Papal See for twenty years, one month,
+        and thirteen days.
+    status: { la: verified, en: verified }