[lldb] Remove out of date comment. NFC (#149908)

Mojo already moved to the main list in 582582fb474b8

lldb/include/lldb/lldb-enumerations.h

@@ -525,8 +525,6 @@ enum LanguageType {
   // Language::SetLanguageFromCString and Language::AsCString assume these can
   // be used as indexes into array g_languages.
   eLanguageTypeMipsAssembler, ///< Mips_Assembler.
-  // Mojo will move to the common list of languages once the DWARF committee
-  // creates a language code for it.
   eNumLanguageTypes
 };