🐛 pkgmismatch warning appears multiple times for same file and line

[maxim-ge]

Summary:

After checking out the following commits:

• reqmd: [434a76b13327a5ad900c879f3d010c72e9b3d2fe](https://github.com/your-org/reqmd/commit/434a76b13327a5ad900c879f3d010c72e9b3d2fe)
• voedger: [b180c666920ef4abed2beb45b65db9eee05b1209](https://github.com/your-org/voedger/commit/b180c666920ef4abed2beb45b65db9eee05b1209)

the following warning is printed three times for the same file and line:

pkgmismatch: CoverageFootnote package (server.users.SendEMail) is not consistent with PackageId in the header (server.users)

File:
server/users/users-emails-send.md:29

Expected:
Only a single warning per file/line mismatch.

Actual:
Three identical warnings appear in output.

Steps to reproduce:

1. Check out the specific commits above in both repos.
2. Run the tool that emits pkgmismatch (likely during coverage or documentation processing).
3. Observe duplicated warning lines.

Suggestion:
Suppress duplicate diagnostics for the same location to improve output clarity.