xiao: keep group name "Seeed Studio"

The supported-boards index derives its group heading from
<board>.name, so the vendor group title stays "Seeed Studio" and the
board model remains in the pnum entry, as originally intended.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: cumin777

boards.txt

@@ -2485,7 +2485,7 @@ GenC0.menu.upload_method.OpenOCDDapLink.debug.server.openocd.scripts.1={runtime.
 ################################################################################
 # Seeed XIAO STM32C5
 # Docs: url=https://www.seeedstudio.com/
-XIAO_STM32C5.name=Seeed Studio XIAO STM32C5
+XIAO_STM32C5.name=Seeed Studio
 
 XIAO_STM32C5.build.core=arduino
 XIAO_STM32C5.build.board=XIAO_STM32C5