doc: prepare miscellaneous docs for new markdown lint rules

Prepare the final few documents that haven't been updated to always use
`[]` with reference links and to escape `[` and `]` for things that
aren't links in markdown files.

PR-URL: #29963
Reviewed-By: Masashi Hirano <shisama07@gmail.com>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>

CPP_STYLE_GUIDE.md

@@ -206,8 +206,8 @@ Use explicit comparisons to `nullptr` when testing pointers, i.e.
 
 ### Ownership and Smart Pointers
 
-* [R.20]: Use `std::unique_ptr` or `std::shared_ptr` to represent ownership
-* [R.21]: Prefer `unique_ptr` over `shared_ptr` unless you need to share
+* [R.20][]: Use `std::unique_ptr` or `std::shared_ptr` to represent ownership
+* [R.21][]: Prefer `unique_ptr` over `shared_ptr` unless you need to share
   ownership
 
 Use `std::unique_ptr` to make ownership transfer explicit. For example:
@@ -286,8 +286,8 @@ data[0] = 12345;
 
 Further reading:
 
-* [ES.48]: Avoid casts
-* [ES.49]: If you must use a cast, use a named cast
+* [ES.48][]: Avoid casts
+* [ES.49][]: If you must use a cast, use a named cast
 
 ### Using `auto`
 

benchmark/README.md

@@ -74,7 +74,7 @@ The common.js module is used by benchmarks for consistency across repeated
 tasks. It has a number of helpful functions and properties to help with
 writing benchmarks.
 
-### createBenchmark(fn, configs[, options])
+### createBenchmark(fn, configs\[, options\])
 
 See [the guide on writing benchmarks](../doc/guides/writing-and-running-benchmarks.md#basics-of-a-benchmark).