The patterns used by [ServeMux] allow multiple spaces matching

Vendoring in std and cmd
========================

The Go command maintains copies of external packages needed by the
standard library in the src/vendor and src/cmd/vendor directories.

There are two modules, std and cmd, defined in src/go.mod and
src/cmd/go.mod. When a package outside std or cmd is imported
by a package inside std or cmd, the import path is interpreted
as if it had a "vendor/" prefix. For example, within "crypto/tls",

Go 1.22 made it an error for a request or response read by a net/http
client or server to have an empty Content-Length header.
This behavior is controlled by the `httplaxcontentlength` setting.

Go 1.22 changed the behavior of ServeMux to accept extended
patterns and unescape both patterns and request paths by segment.
This behavior can be controlled by the
[`httpmuxgo121` setting](/pkg/net/http/#ServeMux).

The [DNSError] type now wraps errors caused by timeouts or cancellation.
For example, `errors.Is(someDNSErr, context.DeadlineExceedeed)`

## For developers

Release notes should be added to `next` by editing existing files or creating
new files. **Do not add RELNOTE=yes comments in CLs.** Instead, add a file to
the CL (or ask the author to do so).

At the end of the development cycle, the files will be merged by being
concatenated in sorted order by pathname. Files in the directory matching the

### Timer changes

Go 1.23 makes two significant changes to the implementation of
[time.Timer] and [time.Ticker].

First, `Timer`s and `Ticker`s that are no longer referred to by the program
become eligible for garbage collection immediately, even if their
`Stop` methods have not been called.
Earlier versions of Go did not collect unstopped `Timer`s until after
they had fired and never collected unstopped `Ticker`s.

which was a source of many inconsistencies and bugs.
This behavior is controlled by the `winsymlink` setting.
For Go 1.23, it defaults to `winsymlink=1`.
Previous versions default to `winsymlink=0`.

On Windows, [EvalSymlinks] no longer tries to normalize
volumes to drive letters, which was not always even possible.
This behavior is controlled by the `winreadlinkvolume` setting.
For Go 1.23, it defaults to `winreadlinkvolume=1`.

Errors returned by [driver.Valuer] implementations are now wrapped for
improved error handling during operations like [DB.Query], [DB.Exec],

The [Stat] function now sets the [ModeSocket] bit for
files that are Unix sockets on Windows. These files are identified

On Windows, [Readlink] no longer tries to normalize volumes
to drive letters, which was not always even possible.
This behavior is controlled by the `winreadlinkvolume` setting.
For Go 1.23, it defaults to `winreadlinkvolume=1`.