Fix duplicated words in comments and docs

[benelog]

Fixes duplicated words (the the, for for) in comments and doc comments.

Only files owned by this repository are touched; occurrences in submodules and subtrees (clippy, miri, rust-analyzer, rustc-dev-guide, compiler-builtins, stdarch) are left for their own repositories.

for for in impl Trait for for<'a> fn(..) and "checks for for-loops" are intentional and untouched.

[rustbot]

Some changes occurred in match checking

cc @Nadrieril

Some changes occurred in tests/codegen-llvm/sanitizer

cc @rcvalle

[rustbot]

Thanks for the pull request, and welcome! The Rust Project is excited to review your changes, and you should hear from @mu001999 (or someone else) some time within the next two weeks.

Please see the contribution instructions for more information. Namely, in order to ensure the minimum review times lag, PR authors and assigned reviewers should ensure that the review label (S-waiting-on-review and S-waiting-on-author) stays updated, invoking these commands when appropriate:

• @rustbot author: the review is finished, PR author should check the comments and take action accordingly
• @rustbot review: the author is ready for a review, this PR will be queued again in the reviewer's queue

Why was this reviewer chosen?

The reviewer was selected based on:

• Owners of files modified in this PR: compiler
• compiler expanded to 75 candidates
• Random selection from 19 candidates

[mu001999]

Thanks for the contribution! As this falls under the policy below, I’m going to close the PR:

Please notice that we don’t accept typography/spellcheck fixes to internal documentation as it’s usually not worth the churn or the review time. Examples of internal documentation is code comments and rustc api docs. However, feel free to fix those if accompanied by other improvements in the same PR.