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/vespers-versicle-common-of-several-martyrs.yml

@@ -4,11 +4,11 @@
 id: vespers-versicle-common-of-several-martyrs
 text:
   la: |
-    ℣. Exsultábunt Sancti in glória.
-    ℟. Lætabúntur in cubílibus suis.
+    V. Exsultábunt Sancti in glória.
+    R. Lætabúntur in cubílibus suis.
   en: |
-    ℣. The saints shall rejoice in glory:
-    ℟. They shall be joyful in their beds.
+    V. The saints shall rejoice in glory:
+    R. They shall be joyful in their beds.
 status:
   la: verified
   en: verified