Downgrade large_digit_groups to pedantic

I believe if the user already decided to put underscores in their
literal, Clippy should be willing to believe that they put a number of
underscores that they felt was readable.

clippy_lints/src/literal_representation.rs

@@ -90,7 +90,7 @@ declare_clippy_lint! {
 /// ```
 declare_clippy_lint! {
     pub LARGE_DIGIT_GROUPS,
-    style,
+    pedantic,
     "grouping digits into groups that are too large"
 }