Update CMakeLists.txt, Fix spelling errors (#3193)

Author: zgzhengSEU

CMakeLists.txt

@@ -215,7 +215,7 @@ if(SPDLOG_FMT_EXTERNAL OR SPDLOG_FMT_EXTERNAL_HO)
     target_compile_definitions(spdlog PUBLIC SPDLOG_FMT_EXTERNAL)
     target_compile_definitions(spdlog_header_only INTERFACE SPDLOG_FMT_EXTERNAL)
 
-    # use external fmt-header-nly
+    # use external fmt-header-only
     if(SPDLOG_FMT_EXTERNAL_HO)
         target_link_libraries(spdlog PUBLIC fmt::fmt-header-only)
         target_link_libraries(spdlog_header_only INTERFACE fmt::fmt-header-only)