cmake: rename FindXMLTO.cmake to correct warning

CMake issues the following developer warning about FindXmlTo: The package name passed to `find_package_handle_standard_args` (XMLTO) does not match the name of the calling package (XmlTo). This can lead to problems in calling code that expects `find_package` result variables (e.g., `_FOUND`) to follow a certain pattern. This corrects that by naming it FindXMLTO.cmake. Signed-off-by: GitHub <noreply@github.com>

Author: alanxz

CMakeLists.txt

@@ -253,8 +253,8 @@ endif()
 
 if(BUILD_TOOLS)
  find_package(POPT REQUIRED)
- if(BUILD_TOOL_DOCS)
- find_package(XmlTo REQUIRED)
+ if(BUILD_TOOLS_DOCS)
+ find_package(XMLTO REQUIRED)
  endif()
  add_subdirectory(tools)
 endif()