docs: Update version number from 5.x to 6.x in README.rst

A quick 'grep "5\.x" . -R' on Documentation shows that README.rst,
2.Process.rst and applying-patches.rst all mention the version number "5.x"
for kernel releases.

As the next release will be version 6.0, updating the version number to 6.x
in README.rst seems reasonable.

The description in 2.Process.rst is just a description of recent kernel
releases, it was last updated in the beginning of 2020, and can be
revisited at any time on a regular basis, independent of changing the
version number from 5 to 6. So, there is no need to update this document
now when transitioning from 5.x to 6.x numbering.

The document applying-patches.rst is probably obsolete for most users
anyway, a reader will sufficiently well understand the steps, even it
mentions version 5 rather than version 6. So, do not update that to a
version 6.x numbering scheme.

Update version number from 5.x to 6.x in README.rst only.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/r/20220824080836.23087-1-lukas.bulwahn@gmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/admin-guide/README.rst

 .. _readme:
 
-Linux kernel release 5.x <http://kernel.org/>
+Linux kernel release 6.x <http://kernel.org/>
 =============================================
 
-These are the release notes for Linux version 5.  Read them carefully,
+These are the release notes for Linux version 6.  Read them carefully,
 as they tell you what this is all about, explain how to install the
 kernel, and what to do if something goes wrong.
 
@@ -63,7 +63,7 @@ Installing the kernel source
    directory where you have permissions (e.g. your home directory) and
    unpack it::
 
-     xz -cd linux-5.x.tar.xz | tar xvf -
+     xz -cd linux-6.x.tar.xz | tar xvf -
 
    Replace "X" with the version number of the latest kernel.
 
@@ -72,12 +72,12 @@ Installing the kernel source
    files.  They should match the library, and not get messed up by
    whatever the kernel-du-jour happens to be.
 
- - You can also upgrade between 5.x releases by patching.  Patches are
+ - You can also upgrade between 6.x releases by patching.  Patches are
    distributed in the xz format.  To install by patching, get all the
    newer patch files, enter the top level directory of the kernel source
-   (linux-5.x) and execute::
+   (linux-6.x) and execute::
 
-     xz -cd ../patch-5.x.xz | patch -p1
+     xz -cd ../patch-6.x.xz | patch -p1
 
    Replace "x" for all versions bigger than the version "x" of your current
    source tree, **in_order**, and you should be ok.  You may want to remove
@@ -85,13 +85,13 @@ Installing the kernel source
    that there are no failed patches (some-file-name# or some-file-name.rej).
    If there are, either you or I have made a mistake.
 
-   Unlike patches for the 5.x kernels, patches for the 5.x.y kernels
+   Unlike patches for the 6.x kernels, patches for the 6.x.y kernels
    (also known as the -stable kernels) are not incremental but instead apply
-   directly to the base 5.x kernel.  For example, if your base kernel is 5.0
-   and you want to apply the 5.0.3 patch, you must not first apply the 5.0.1
-   and 5.0.2 patches. Similarly, if you are running kernel version 5.0.2 and
-   want to jump to 5.0.3, you must first reverse the 5.0.2 patch (that is,
-   patch -R) **before** applying the 5.0.3 patch. You can read more on this in
+   directly to the base 6.x kernel.  For example, if your base kernel is 6.0
+   and you want to apply the 6.0.3 patch, you must not first apply the 6.0.1
+   and 6.0.2 patches. Similarly, if you are running kernel version 6.0.2 and
+   want to jump to 6.0.3, you must first reverse the 6.0.2 patch (that is,
+   patch -R) **before** applying the 6.0.3 patch. You can read more on this in
    :ref:`Documentation/process/applying-patches.rst <applying_patches>`.
 
    Alternatively, the script patch-kernel can be used to automate this
@@ -114,7 +114,7 @@ Installing the kernel source
 Software requirements
 ---------------------
 
-   Compiling and running the 5.x kernels requires up-to-date
+   Compiling and running the 6.x kernels requires up-to-date
    versions of various software packages.  Consult
    :ref:`Documentation/process/changes.rst <changes>` for the minimum version numbers
    required and how to get updates for these packages.  Beware that using
@@ -132,12 +132,12 @@ Build directory for the kernel
    place for the output files (including .config).
    Example::
 
-     kernel source code: /usr/src/linux-5.x
+     kernel source code: /usr/src/linux-6.x
      build directory:    /home/name/build/kernel
 
    To configure and build the kernel, use::
 
-     cd /usr/src/linux-5.x
+     cd /usr/src/linux-6.x
      make O=/home/name/build/kernel menuconfig
      make O=/home/name/build/kernel
      sudo make O=/home/name/build/kernel modules_install install