merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/Documentation/urls.txt

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+GIT URLS[[URLS]]
+----------------
+
+In general, URLs contain information about the transport protocol, the
+address of the remote server, and the path to the repository.
+Depending on the transport protocol, some of this information may be
+absent.
+
+Git supports ssh, git, http, and https protocols (in addition, ftp,
+and ftps can be used for fetching, but this is inefficient and
+deprecated; do not use it).
+
+The native transport (i.e. git:// URL) does no authentication and
+should be used with caution on unsecured networks.
+
+The following syntaxes may be used with them:
+
+- ssh://{startsb}user@{endsb}host.xz{startsb}:port{endsb}/path/to/repo.git/
+- git://host.xz{startsb}:port{endsb}/path/to/repo.git/
+- http{startsb}s{endsb}://host.xz{startsb}:port{endsb}/path/to/repo.git/
+- ftp{startsb}s{endsb}://host.xz{startsb}:port{endsb}/path/to/repo.git/
+
+An alternative scp-like syntax may also be used with the ssh protocol:
+
+- {startsb}user@{endsb}host.xz:path/to/repo.git/
+
+This syntax is only recognized if there are no slashes before the
+first colon. This helps differentiate a local path that contains a
+colon. For example the local path `foo:bar` could be specified as an
+absolute path or `./foo:bar` to avoid being misinterpreted as an ssh
+url.
+
+The ssh and git protocols additionally support ~username expansion:
+
+- ssh://{startsb}user@{endsb}host.xz{startsb}:port{endsb}/~{startsb}user{endsb}/path/to/repo.git/
+- git://host.xz{startsb}:port{endsb}/~{startsb}user{endsb}/path/to/repo.git/
+- {startsb}user@{endsb}host.xz:/~{startsb}user{endsb}/path/to/repo.git/
+
+For local repositories, also supported by Git natively, the following
+syntaxes may be used:
+
+- /path/to/repo.git/
+- \file:///path/to/repo.git/
+
+ifndef::git-clone[]
+These two syntaxes are mostly equivalent, except when cloning, when
+the former implies --local option. See linkgit:git-clone[1] for
+details.
+endif::git-clone[]
+
+ifdef::git-clone[]
+These two syntaxes are mostly equivalent, except the former implies
+--local option.
+endif::git-clone[]
+
+When Git doesn't know how to handle a certain transport protocol, it
+attempts to use the 'remote-<transport>' remote helper, if one
+exists. To explicitly request a remote helper, the following syntax
+may be used:
+
+- <transport>::<address>
+
+where <address> may be a path, a server and path, or an arbitrary
+URL-like string recognized by the specific remote helper being
+invoked. See linkgit:gitremote-helpers[7] for details.
+
+If there are a large number of similarly-named remote repositories and
+you want to use a different format for them (such that the URLs you
+use will be rewritten into URLs that work), you can create a
+configuration section of the form:
+
+------------
+	[url "<actual url base>"]
+		insteadOf = <other url base>
+------------
+
+For example, with this:
+
+------------
+	[url "git://git.host.xz/"]
+		insteadOf = host.xz:/path/to/
+		insteadOf = work:
+------------
+
+a URL like "work:repo.git" or like "host.xz:/path/to/repo.git" will be
+rewritten in any context that takes a URL to be "git://git.host.xz/repo.git".
+
+If you want to rewrite URLs for push only, you can create a
+configuration section of the form:
+
+------------
+	[url "<actual url base>"]
+		pushInsteadOf = <other url base>
+------------
+
+For example, with this:
+
+------------
+	[url "ssh://example.org/"]
+		pushInsteadOf = git://example.org/
+------------
+
+a URL like "git://example.org/path/to/repo.git" will be rewritten to
+"ssh://example.org/path/to/repo.git" for pushes, but pulls will still
+use the original URL.