[clang-tools-extra] [clang-tidy] Clarify diagnostics of bugprone-sizeof-expression (PR #95550)

[Danny Mösch via cfe-commits]

SimplyDanny wrote:

> If there is no feedback on the separator mark bikeshedding (which is understandable -- it's a very minor question), I'll merge this commit on Thursday.

The reason for the colon appears plausible to me. What I can't judge is if this is contradicting the style typically used in messages emitted by other checks. Be that as it may, it can be changed afterwards very easily if anyone is strict on that. So from my side, you can go ahead and merge this.

https://github.com/llvm/llvm-project/pull/95550