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/temporal/immaculate-heart-of-mary-collect.yml

@@ -10,7 +10,7 @@ text:
     vívere valeámus.
     Per Dóminum ejúsdem Fílii tui: qui tecum vivit et regnat in unitáte Spíritus
     Sancti, Deus, per ómnia sǽcula sæculórum.
-    ℟. Amen.
+    R. Amen.
   en: |
     Let us pray.
     Almighty everlasting God, who hast prepared in the heart of Blessed Virgin
@@ -19,7 +19,7 @@ text:
     to live according to thy heart.
     Through the same thy Son our Lord, Who liveth and reigneth with thee, in the
     unity of the Holy Ghost, God, world without end.
-    ℟. Amen.
+    R. Amen.
 status:
   la: verified
   en: verified