This greatly simplifies a large portion of the underlying infrastructure, allows for lookups of singleton classes to be much more efficient and always thread-safe(no locking). As a result of this, the dialect symbol registry has been removed as it is no longer necessary.
For users broken by this change, an alert was sent out(https://llvm.discourse.group/t/removing-kinds-from-attributes-and-types) that helps prevent a majority of the breakage surface area. All that should be necessary, if the advice in that alert was followed, is removing the kind passed to the ::get methods.
clang-tidy: warning: invalid case style for function 'isa_fir_type' [readability-identifier-naming]
not useful
clang-tidy: warning: use of function template name with no prior declaration in function call with explicit template arguments is a C++20 extension [clang-diagnostic-c++20-extensions]
not useful