[clang] [clang] Add Bytes/Column types to TextDiagnostic (PR #165541)

[Timm Baeder via cfe-commits]

tbaederr wrote:

> In my experience, it’s usually easier to (ab)use enums for this, i.e.
> 
> ```c++
> enum class Bytes : unsigned;
> enum class Columns : unsigned;
> ```
> 
> and then define additional operators as needed.

Well it's not an enumeration and I can't define member functions like that. This is also similar to the `Bytes` struct I have already added [elsewhere](https://github.com/llvm/llvm-project/blob/main/clang/lib/AST/ByteCode/BitcastBuffer.h#L55)

https://github.com/llvm/llvm-project/pull/165541