[clang] [analyzer] Update the undefined assignment checker diagnostics to not use the term 'garbage' (PR #126596)

[David Tarditi via cfe-commits]

dtarditi wrote:

@Xazax-hun and @haoNoQ.   Could one of you review this or assign it to someone to review?  Thanks.


https://github.com/llvm/llvm-project/pull/126596