Normalize versicle notation to plain V./R. across propers

Unicode ℣/℟ (U+2123/U+211F) were mixed unpredictably with plain V./R.
across ~550 proper YAML files, sometimes within the same file. Screen
readers can't announce the unicode glyphs. Replace all instances with
plain text.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QC6jHsj75xcsTkapqJR6fD

src/data/propers/common/finding-of-st-stephen-commemoration.yml

@@ -14,7 +14,7 @@ text:
     Orémus.
     Da nobis, quǽsumus, Dómine, imitári quod cólimus: ut discámus et inimícos dilígere; quia ejus Inventiónem celebrámus, qui novit étiam pro persecutóribus exoráre Dóminum nostrum Jesum Christum Fílium tuum:
     Qui tecum vivit et regnat in unitáte Spíritus Sancti, Deus, per ómnia sǽcula sæculórum.
-    ℟. Amen.
+    R. Amen.
   en: |
     Ant. And Stephen, full of grace * and fortitude, did great signs among the people.
     V. The righteous shall flourish like the palm tree:
@@ -22,7 +22,7 @@ text:
     Let us pray.
     Grant us, we beseech thee, O Lord, so to imitate what we revere, that we may learn to love even our enemies; for we celebrate the Finding of the holy body of him who knew how to pray for his very persecutors to our Lord Jesus Christ:
     Who with thee liveth and reigneth, in the unity of the Holy Spirit, God, world without end.
-    ℟. Amen.
+    R. Amen.
 status:
   la: draft
   en: draft