dim: Update update-branches

It's been years since drm-intel had only one maintainer, and the
primary use-case for dim ub was only to sync between machines. Update
the docs to reflect this, to avoid misleading committers. Also update
the maintainer-tools branch, which is something Paulo's script also
does.

Motivated because Paulo typed an actualize.sh script which does
exactly what dim ub is meant to do.

v2: Also update quickstart guide.

v3: And spelling fixes.

v4: Fix title and only update maintainer-tools when not a private
branch is checkout out (Jani).

Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

dim

@@ -1293,6 +1293,12 @@ function dim_update_branches
 	dim_checkout drm-intel-next
 	$DRY git reset --hard $DIM_DRM_INTEL_REMOTE/drm-intel-next
 
+	cd $DIM_PREFIX/maintainer-tools
+	if git branch | grep maintainer-tools | grep '\*' ; then
+		echo "Updating maintainer-tools ..."
+		git pull --rebase
+	fi
+
 	update_rerere_cache
 }
 

dim.rst

@@ -74,11 +74,8 @@ Setup git maintainer branches in the given prefix.
 
 update-branches
 ---------------
-Updates all maintainer branches. Only needs to be run to synchronize branches
-between different machines (or maintainers fwiw). As long a given branch is
-always maintained from the same machine, even if different branches are
-maintained on different machines (by different maintainers), there's no need to
-run this command.
+Updates all maintainer branches. Useful to synchronize all branches when other
+maintainers and committers pushed patches meanwhile.
 
 status
 ------
@@ -408,6 +405,10 @@ corresponding to this repository is defined by DIM_DRM_INTEL in your .dimrc.
 You should also have directories called maintainer-tools, drm-tip (for
 rebuilding the tree), and drm-intel-rerere for some dim-internal book-keeping.
 
+If someone else has pushed patches first resync using::
+
+   $ dim update-branches
+
 Applying patches to dinq is done in the main repository with::
 
     $ cat patch.mbox | dim apply-queued