revert(3p/git): Revert merge of git upstream at v2.26.2

This causes cgit to serve error pages, which is undesirable.

This reverts commit 5229c9b232, reversing
changes made to f2b211131f.

third_party/git/Documentation/git-submodule.txt

@@ -16,7 +16,6 @@ SYNOPSIS
 'git submodule' [--quiet] deinit [-f|--force] (--all|[--] <path>...)
 'git submodule' [--quiet] update [<options>] [--] [<path>...]
 'git submodule' [--quiet] set-branch [<options>] [--] <path>
-'git submodule' [--quiet] set-url [--] <path> <newurl>
 'git submodule' [--quiet] summary [<options>] [--] [<path>...]
 'git submodule' [--quiet] foreach [--recursive] <command>
 'git submodule' [--quiet] sync [--recursive] [--] [<path>...]
@@ -81,9 +80,6 @@ status [--cached] [--recursive] [--] [<path>...]::
 	does not match the SHA-1 found in the index of the containing
 	repository and `U` if the submodule has merge conflicts.
 +
-If `--cached` is specified, this command will instead print the SHA-1
-recorded in the superproject for each submodule.
-+
 If `--recursive` is specified, this command will recurse into nested
 submodules, and show their status as well.
 +
@@ -133,12 +129,11 @@ If you really want to remove a submodule from the repository and commit
 that use linkgit:git-rm[1] instead. See linkgit:gitsubmodules[7] for removal
 options.
 
-update [--init] [--remote] [-N|--no-fetch] [--[no-]recommend-shallow] [-f|--force] [--checkout|--rebase|--merge] [--reference <repository>] [--depth <depth>] [--recursive] [--jobs <n>] [--[no-]single-branch] [--] [<path>...]::
+update [--init] [--remote] [-N|--no-fetch] [--[no-]recommend-shallow] [-f|--force] [--checkout|--rebase|--merge] [--reference <repository>] [--depth <depth>] [--recursive] [--jobs <n>] [--] [<path>...]::
 +
 --
 Update the registered submodules to match what the superproject
-expects by cloning missing submodules, fetching missing commits
-in submodules and updating the working tree of
+expects by cloning missing submodules and updating the working tree of
 the submodules. The "updating" can be done in several ways depending
 on command line options and the value of `submodule.<name>.update`
 configuration variable. The command line option takes precedence over
@@ -178,18 +173,12 @@ submodule with the `--init` option.
 If `--recursive` is specified, this command will recurse into the
 registered submodules, and update any nested submodules within.
 --
-set-branch (-b|--branch) <branch> [--] <path>::
-set-branch (-d|--default) [--] <path>::
+set-branch ((-d|--default)|(-b|--branch <branch>)) [--] <path>::
 	Sets the default remote tracking branch for the submodule. The
 	`--branch` option allows the remote branch to be specified. The
 	`--default` option removes the submodule.<name>.branch configuration
 	key, which causes the tracking branch to default to 'master'.
 
-set-url [--] <path> <newurl>::
-	Sets the URL of the specified submodule to <newurl>. Then, it will
-	automatically synchronize the submodule's new remote URL
-	configuration.
-
 summary [--cached|--files] [(-n|--summary-limit) <n>] [commit] [--] [<path>...]::
 	Show commit summary between the given commit (defaults to HEAD) and
 	working tree/index. For a submodule in question, a series of commits
@@ -229,7 +218,7 @@ As an example, the command below will show the path and currently
 checked out commit for each submodule:
 +
 --------------
-git submodule foreach 'echo $sm_path `git rev-parse HEAD`'
+git submodule foreach 'echo $path `git rev-parse HEAD`'
 --------------
 
 sync [--recursive] [--] [<path>...]::
@@ -248,7 +237,7 @@ registered submodules, and sync any nested submodules within.
 
 absorbgitdirs::
 	If a git directory of a submodule is inside the submodule,
-	move the git directory of the submodule into its superproject's
+	move the git directory of the submodule into its superprojects
 	`$GIT_DIR/modules` path and then connect the git directory and
 	its working directory by setting the `core.worktree` and adding
 	a .git file pointing to the git directory embedded in the
@@ -430,10 +419,6 @@ options carefully.
 	Clone new submodules in parallel with as many jobs.
 	Defaults to the `submodule.fetchJobs` option.
 
---[no-]single-branch::
-	This option is only valid for the update command.
-	Clone only one branch during update: HEAD or one specified by --branch.
-
 <path>...::
 	Paths to submodule(s). When specified this will restrict the command
 	to only operate on the submodules found at the specified paths.