Update some date-check comments

I removed one of them because it doesn't seem necessary.

src/overview.md

@@ -262,7 +262,7 @@ Moreover, the compiler wasn't originally built to use a query system; the query
 system has been retrofitted into the compiler, so parts of it are not query-fied
 yet. Also, LLVM isn't our code, so that isn't querified either. The plan is to
 eventually query-fy all of the steps listed in the previous section,
-but as of <!-- date: 2021-02 --> February 2021, only the steps between HIR and
+but as of <!-- date: 2021-11 --> February 2021, only the steps between HIR and
 LLVM IR are query-fied. That is, lexing, parsing, name resolution, and macro
 expansion are done all at once for the whole program.
 

src/rustdoc-internals.md

@@ -66,7 +66,7 @@ these passes, please let us know!)
 
 [44136]: https://github.com/rust-lang/rust/issues/44136
 
-Here is the list of passes as of <!-- date: 2021-02 --> February 2021:
+Here is the list of passes as of <!-- date: 2021-10 --> October 2021:
 
 - `calculate-doc-coverage` calculates information used for the `--show-coverage`
   flag.

src/tests/intro.md

@@ -126,8 +126,7 @@ essence, it runs `./x.py test` after building for each of them.
 
 The integration bot [bors] is used for coordinating merges to the master branch.
 When a PR is approved, it goes into a [queue] where merges are tested one at a
-time on a wide set of platforms using GitHub Actions (as of <!-- date: 2021-01
+time on a wide set of platforms using GitHub Actions. Due to the limit on the
---> January 2021, over 50 different configurations). Due to the limit on the
 number of parallel jobs, we run CI under the [rust-lang-ci] organization except
 for PRs. Most platforms only run the build steps, some run a restricted set of
 tests, only a subset run the full suite of tests (see Rust's [platform tiers]).