Rollup merge of #147489 - chenyukang:yukang-prefer-repeat-n, r=Kivooeo,oli-obk

Prefer to use repeat_n over repeat().take()

More from https://github.com/rust-lang/rust/pull/147464, but batch processed with `ast-grep` to find and replace.

second commit add notes for library: affaf532f9

r? ``@RalfJung``

compiler/rustc_const_eval/src/const_eval/error.rs

@@ -110,7 +110,7 @@ pub fn get_span_and_frames<'tcx>(
             if frame.times < 3 {
                 let times = frame.times;
                 frame.times = 0;
-                frames.extend(std::iter::repeat(frame).take(times as usize));
+                frames.extend(std::iter::repeat_n(frame, times as usize));
             } else {
                 frames.push(frame);
             }

compiler/rustc_const_eval/src/util/check_validity_requirement.rs

@@ -59,7 +59,7 @@ fn check_validity_requirement_strict<'tcx>(
     if kind == ValidityRequirement::Zero {
         cx.write_bytes_ptr(
             allocated.ptr(),
-            std::iter::repeat(0_u8).take(ty.layout.size().bytes_usize()),
+            std::iter::repeat_n(0_u8, ty.layout.size().bytes_usize()),
         )
         .expect("failed to write bytes for zero valid check");
     }