fix man installation dir

PiperOrigin-RevId: 830898574

Author: eustas

CMakeLists.txt

@@ -386,11 +386,11 @@ endif()  # BROTLI_BUNDLED_MODE
 
 if (BROTLI_BUILD_TOOLS)
   install(FILES "docs/brotli.1"
-    DESTINATION "${CMAKE_INSTALL_FULL_MANDIR}/man1")
+    DESTINATION "${CMAKE_INSTALL_MANDIR}/man1")
 endif()
 
 install(FILES docs/constants.h.3 docs/decode.h.3 docs/encode.h.3 docs/types.h.3
-  DESTINATION "${CMAKE_INSTALL_FULL_MANDIR}/man3")
+  DESTINATION "${CMAKE_INSTALL_MANDIR}/man3")
 
 if (ENABLE_COVERAGE STREQUAL "yes")
   setup_target_for_coverage(coverage test coverage)