[YUNIKORN-2591] Document placement rules always (apache#426)

Remove mention of no placement rules and set it to use the provided rule
if no rules are defined. This is the same behaviour as it was without
using placement rules always.

Closes: apache#426

Signed-off-by: Wilfred Spiegelenburg <[email protected]>

docs/user_guide/queue_config.md

@@ -201,7 +201,8 @@ partitions:
 The placement rules are defined and documented in the [placement rule](placement_rules.md) document.
 
 Each partition can have only one set of placement rules defined. 
-If no rules are defined the placement manager is not started and each application *must* have a queue set on submit.
+If no rules are defined, [provided rule](placement_rules#provided-rule) will be applied.
+Each application *must* have a queue set on submit.
 
 ### Limits
 Limits define a set of limit objects for a queue, and can be set on a queue at any level.

versioned_docs/version-1.4.0/user_guide/queue_config.md

@@ -202,7 +202,8 @@ partitions:
 The placement rules are defined and documented in the [placement rule](placement_rules.md) document.
 
 Each partition can have only one set of placement rules defined. 
-If no rules are defined the placement manager is not started and each application *must* have a queue set on submit.
+If no rules are defined, [provided rule](placement_rules#provided-rule) will be applied.
+Each application *must* have a queue set on submit.
 
 ### Statedump filepath
 

versioned_docs/version-1.5.0/user_guide/queue_config.md

@@ -201,7 +201,8 @@ partitions:
 The placement rules are defined and documented in the [placement rule](placement_rules.md) document.
 
 Each partition can have only one set of placement rules defined. 
-If no rules are defined the placement manager is not started and each application *must* have a queue set on submit.
+If no rules are defined, [provided rule](placement_rules#provided-rule) will be applied.
+Each application *must* have a queue set on submit.
 
 ### Limits
 Limits define a set of limit objects for a queue, and can be set on a queue at any level.