Update ReleaseNotes.txt

Add note to XSLT section

Author: sarcanon

ReleaseNotes.txt

@@ -16,6 +16,7 @@ Latest version
  * XSLT: tranlating "uU" to "vV" in diplomatic for Latin context (tpl-text.xsl) [Markup List: https://www.jiscmail.ac.uk/cgi-bin/wa-jisc.exe?A2=ind2506&L=EPIDOC-MARKUP&O=D&X=A68F605AD579DC5837&Y=souchon.nicolas.ns%40gmail.com&P=13370]
  * XSLT: adding macron, overline and breve to diacritics stripped in diplomatic (tpl-text.xsl)
  * XSLT: Fix missing gap content in text output (txt-teigap.xsl)
+ * XSLT: Multiple project-specific changes affecting only MedCyprus and Wingspread.
 
  * EFES: Release 2025-02, aligned with EpiDoc 9.8