ref-manual: drop "partition" as a wic kickstart command

The kickstart reference documents "partition" as a synonym for "part".
wic does not accept it: its parser registers only part, bootloader and
include, so a .wks line beginning "partition" fails with an
invalid-choice error.

The synonym was real while wic used a bundled pykickstart, whose command
table mapped both spellings to one handler. Replacing that with a parser
carrying only the options wic uses kept "part" alone, and the manual was
not updated to match.

AI-Generated: codex/claude-opus 5 (xhigh)
(From yocto-docs rev: a34ca7357403feea970d27909e3529cf18e708d5)

Signed-off-by: Trevor Woerner <twoerner@gmail.com>
Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
(cherry picked from commit 3a52e763346647f2edf23dee4ed28ede5ba5c22b)
Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Paul Barker <paul@pbarker.dev>

documentation/ref-manual/kickstart.rst

@@ -26,14 +26,13 @@ modifications to reflect Wic capabilities. You can see the original
 documentation for those commands at the following link:
 https://pykickstart.readthedocs.io/en/latest/kickstart-docs.html
 
-Command: part or partition
-==========================
+Command: part
+=============
 
-Either of these commands creates a partition on the system and uses the
+This command creates a partition on the system and uses the
 following syntax::
 
    part [mntpoint]
-   partition [mntpoint]
 
 If you do not
 provide mntpoint, Wic creates a partition but does not mount it.
@@ -64,7 +63,7 @@ Here is an example that uses "/" as the mountpoint. The command uses
       part / --source rootfs --ondisk sdb --fstype=ext3 --label platform --align 1024
 
 Here is a list that describes other supported options you can use with
-the ``part`` and ``partition`` commands:
+the ``part`` command:
 
 -  ``--size``: The minimum partition size. Specify as an integer value
    optionally followed by one of the units "k" / "K" for kibibyte,

documentation/ref-manual/variables.rst

@@ -4168,7 +4168,7 @@ system and gives an overview of their function and contents.
       When using Wic tool, beware that a second overhead factor is also applied.
       This overhead value is defined by the ``--overhead-factor`` option, which
       defaults to "1.3" when omitted. See the
-      :ref:`ref-manual/kickstart:command: part or partition` chapter in
+      :ref:`ref-manual/kickstart:command: part` chapter in
       :doc:`/ref-manual/kickstart` for details.
 
    :term:`IMAGE_PKGTYPE`