Resource adapters subsystem - small user experience enhancements

Here's a number of typos or suggestions for user experience enhancements in the resource-adapters subsystem.

1, Schema file (docs/schema/wildfly-resource-adapters_4_0.xsd) has IMHO bad wording on the fair element in the complex type poolType. This is the same as in JBEAP-7018 in the datasources subsystem.
2, (schema file) The same fair element name is not aligned with the pool-fair attribute in the datasources subsystem. Both of these could be called the same (pool-fair).
3, (schema file) recover-credential element on complex type recoverType has grammatical mistakes in its description: "Note: if this credential are not specified the security credential are used for recover too" -> "Note: if this credential is not specified the security credential is used for recovery too"
4, (subsystem from now on) background validation on connection-definitions says it requires server restarts, but its restart-required value is no-services. Doing /subsystem=resource-adapters/resource-adapter=new-resource-adapter/connection-definitions=new-connection-definition:write-attribute(name=background-validation,value=false) does not prompt the user to restart the server.
5, The same goes for background-validation-millis: /subsystem=resource-adapters/resource-adapter=new-resource-adapter/connection-definitions=new-connection-definition:write-attribute(name=background-validation-millis,value=12000)
6, The same goes for idle-timeout-minutes: /subsystem=resource-adapters/resource-adapter=new-resource-adapter/connection-definitions=new-connection-definition:write-attribute(name=idle-timeout-minutes,value=4)
7, The same goes for pool-prefill: /subsystem=resource-adapters/resource-adapter=new-resource-adapter/connection-definitions=new-connection-definition:write-attribute(name=pool-prefill,value=true)
8, idle-timeout-millis can be lower than zero:
/subsystem=resource-adapters/resource-adapter=new-resource-adapter/connection-definitions=new-connection-definition:write-attribute(name=idle-timeout-minutes,value=-4)
9, flush-strategy on connection-definitions has bad valid values in its description - this is the same as in the datasources subsystem - JBEAP-7018