Fix grammatical error in lint_groups_priority diagnostic suggestion

[Shivangisharma4]

Summary

Currently, when the clippy::lint_groups_priority lint is triggered, the diagnostic suggestion is missing a comma, which makes the phrasing grammatically confusing.

The current output is:

"to have lints override the group set `{group_name}` to a lower priority"

Proposed Fix: Add a comma to separate the clauses for better readability:

"to have lints override the group, set `{group_name}` to a lower priority"

Implementation details: The missing punctuation is located in clippy_lints/src/cargo/lint_groups_priority.rs.
Fixing this will also require running cargo uibless to update the corresponding .stderr files in the ui-cargo/lint_groups_priority test suite.

Reproducer

Code:

<code>

Current output:

Desired output:

Version

Additional Labels

No response