doc: update man page for flux-config-accounting

Problem: The man page for flux-config-accounting is out-of-date and
needs to be updated to include how to define priorities for queues to
be read and used by the priority plugin.

Add a section to the man page explaining how to set integer priorities
for queues in a TOML configuration file.

doc/man5/flux-config-accounting.rst

@@ -6,6 +6,9 @@ flux-config-accounting(5)
 DESCRIPTION
 ===========
 
+accounting.factor-weights
+-------------------------
+
 The flux-accounting priority plugin can be configured to assign different
 weights to the different factors used when calculating a job's priority.
 Assigning a higher weight to a factor will result in it having more
@@ -24,7 +27,7 @@ The ``accounting.factor-weights`` sub-table may contain the following keys:
 
 
 KEYS
-====
+^^^^
 
 fairshare
     Integer value that represents the weight to be associated with an
@@ -36,10 +39,36 @@ queue
 
 
 EXAMPLE
-=======
+^^^^^^^
 
 ::
 
    [accounting.factor-weights]
    fairshare = 10000
    queue = 1000
+
+accounting.queue-priorities
+---------------------------
+
+The priority plugin's queues can also be configured to have a different
+associated integer priority in the TOML file. Queues can positively or
+negatively affect a job's calculated priority depending on the priority
+assigned to each one. By default, queues have an associated priority of 0,
+meaning they do not affect a job's priority at all.
+
+If a queue defined in the config file is unknown to the priority plugin, it
+will add the queue to its internal map. Otherwise, it will update the queue's
+priority with the new value.
+
+The ``accounting.queue-priorities`` sub-table should list any configured queue
+as the key and its associated integer priority as the value.
+
+EXAMPLE
+^^^^^^^
+
+::
+
+   [accounting.queue-priorities]
+   bronze=100
+   silver=200
+   gold=300