Confirm merge from FromPublicMasterBranch to main to sync with https://github.com/MicrosoftDocs/cpp-docs (branch main) (#6756)

* Update Vectorized STL algorithm documentation to reflect the current stae (#5937)

Since the last update:
 * ARM64 and ARM64EC vectorization was added. Mention of x64 and x86 is removed, as vectorization is now supported on any target, except deprecated `/clr:pure` and `/clr:safe` modes.
 * `includes` is now manually vectorized too
 * `replace_copy` is now manually vectorized too

Also moved `find_end` to `search` / `search_n` group, where it fits better.

* Update header-files-cpp.md (#5938)

Clarify intent of section

* Update documentation on accessing System.String characters (#5940)

* Update documentation on accessing System.String characters

Added important note about treating interior pointers as const and linked to unsafe code best practices.

* Update docs/dotnet/how-to-access-characters-in-a-system-string.md

Co-authored-by: Jan Kotas <jkotas@microsoft.com>

* Apply suggestions from code review

Co-authored-by: Aaron R Robinson <arobins@microsoft.com>

* Apply suggestions from code review

Co-authored-by: Aaron R Robinson <arobins@microsoft.com>

---------

Co-authored-by: Jan Kotas <jkotas@microsoft.com>

---------

Co-authored-by: learn-build-service-prod[bot] <113403604+learn-build-service-prod[bot]@users.noreply.github.com>
Co-authored-by: Learn Build Service GitHub App <Learn Build Service LearnBuild@microsoft.com>
Co-authored-by: Alex Guteniev <gutenev@gmail.com>
Co-authored-by: veganaiZe <7102064+veganaiZe@users.noreply.github.com>
Co-authored-by: Aaron R Robinson <arobins@microsoft.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>

Author: 6 people

docs/dotnet/how-to-access-characters-in-a-system-string.md

@@ -9,6 +9,10 @@ helpviewer_keywords: ["characters [C++], accessing in System::String", "examples
 
 You can access characters of a <xref:System.String> object for high-performance calls to unmanaged functions that take `wchar_t*` strings. The method yields an interior pointer to the first character of the <xref:System.String> object. This pointer can be manipulated directly or pinned and passed to a function expecting an ordinary **`wchar_t`** string.
 
+> [!IMPORTANT]
+> Interior pointers into <xref:System.String> objects must be treated as `const`. A <xref:System.String> object is considered immutable and changing its content can destabilize the runtime.
+> For more information see [Unsafe code best practices - 17. String mutations](/dotnet/standard/unsafe-code/best-practices).
+
 ## Examples
 
 `PtrToStringChars` returns a <xref:System.Char>, which is an interior pointer (also known as a `byref`). As such, it is subject to garbage collection. You don't have to pin this pointer unless you're going to pass it to a native function.