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-the-holy-cross-collect.yml

@@ -11,7 +11,7 @@ text:
     concéde; ut vitális ligni prétio, ætérnæ vitæ suffrágia consequámur:
     Qui vivis et regnas cum Deo Patre, in unitáte Spíritus Sancti, Deus, per ómnia sǽcula
     sæculórum.
-    ℟. Amen.
+    R. Amen.
   en: |
     Let us pray.
     O God, Who didst cause that the Cross of our salvation should in most honourable wise be
@@ -20,7 +20,7 @@ text:
     finally attain unto life eternal.
     Who livest and reignest with God the Father, in the unity of the Holy Ghost, God, world
     without end.
-    ℟. Amen.
+    R. Amen.
 status:
   la: verified
   en: verified