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/decollation-of-st-john-baptist-collect.yml

@@ -6,12 +6,12 @@ text:
     Orémus.
     Sancti Joánnis Baptístæ Præcursóris et Mártyris tui, quǽsumus, Dómine, veneránda festívitas: salutáris auxílii nobis præstet efféctum:
     Qui vivis et regnas cum Deo Patre, in unitáte Spíritus Sancti, Deus, per ómnia sǽcula sæculórum.
-    ℟. Amen.
+    R. Amen.
   en: |
     Let us pray.
     Lord, we beseech thee, that the keeping of this honourable feastday in memory of the holy Baptist John, thy Fore-runner, and thy Martyr, may be a mean to draw upon us the effectual outpouring of thy saving help.
     Who livest and reignest with God the Father in the unity of the Holy Spirit, God, world without end.
-    ℟. Amen.
+    R. Amen.
 status:
   la: verified
   en: verified