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/nativity-of-st-john-the-baptist-collect.yml

@@ -7,12 +7,12 @@ text:
     Orémus.
     Deus, qui præséntem diem honorábilem nobis in beáti Joánnis nativitáte fecísti: da pópulis tuis spirituálium grátiam gaudiórum; et ómnium fidélium mentes dírige in viam salútis ætérnæ.
     Per Dóminum nostrum Jesum Christum, Fílium tuum: qui tecum vivit et regnat in unitáte Spíritus Sancti, Deus, per ómnia sǽcula sæculórum.
-    ℟. Amen.
+    R. Amen.
   en: |
     Let us pray.
     O God, Who hast made this day to be honourable in our eyes because of the Birth of the blessed John, graciously quicken thy people with spiritual joy, and order the minds of all the faithful in the way of everlasting salvation.
     Through Jesus Christ, 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