Improve kernel settings doc for VMs

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Author: pombredanne

README.rst

@@ -64,6 +64,7 @@ file cannot be read as required by libguestfish.
 
 Run this command as a temporary and immediate fix::
 
+    sudo chmod 0644 /boot/vmlinuz-*
     for k in /boot/vmlinuz-*
         do sudo dpkg-statoverride --add --update root root 0644 /boot/vmlinuz-$k
     done
@@ -87,9 +88,9 @@ https://bugs.launchpad.net/ubuntu/+source/linux/+bug/759725/comments/3 ::
 
 2. Set executable permissions::
 
-    sudo chmod +x /etc/kernel/postinst.d/statoverride 
+    sudo chmod +x /etc/kernel/postinst.d/statoverride
 
-See also for a complete discussion:
+See also these links for a complete discussion:
 
     - https://bugs.launchpad.net/ubuntu/+source/linux/+bug/759725
     - https://bugzilla.redhat.com/show_bug.cgi?id=1670790
@@ -109,15 +110,13 @@ ExtractCode will use these environment variables if set:
   shared library used to support some of the archive formats. If not provided,
   ExtractCode will look for a plugin-provided libarchive library path. See 
   https://github.com/nexB/scancode-plugins/tree/main/builtins for such plugins.
-
   If no plugin contributes libarchive, then a final attempt is made to look for
   it in the PATH using standard DLL loading techniques.
 
 - EXTRACTCODE_7Z_PATH : the path to the ``7z`` 7zip executable used to support
   some of the archive formats. If not provided, ExtractCode will look for a
   plugin-provided 7z executable path. See
   https://github.com/nexB/scancode-plugins/tree/main/builtins for such plugins.
-
   If no plugin contributes 7z, then a final attempt is made to look for
   it in the PATH.
 

src/extractcode/vmimage.py

@@ -42,14 +42,17 @@
     'WARNING: guestfish executable is not installed. '
     'Unable to extract virtual machine image: you need to install the '
     'guestfish tool from libguestfs and extra FS drivers if needed. '
-    'See the ExtractCode README.rst and https://libguestfs.org/ for details.'
+    'See the ExtractCode README.rst at '
+    'https://github.com/nexB/extractcode/blob/main/README.rst '
+    'and https://libguestfs.org/ for details.'
 )
 
 GUESTFISH_KERNEL_NOT_READABLE = (
 '''libguestfs requires the kernel executable to be readable.
 This is the case by default on most Linux distributions except on Ubuntu.
 Please follow the instructions in ExtractCode installation guide to make this happen.
-See the ExtractCode README.rst for details.
+See deatils in the ExtractCode README.rst at:
+https://github.com/nexB/extractcode/blob/main/README.rst '
 ''')
 
 EXTRACTCODE_GUESTFISH_PATH_ENVVAR = 'EXTRACTCODE_GUESTFISH_PATH'