Fix docs issues. (ansible-collections#797)

Fix docs issues.

SUMMARY
Fix some docs issues exhibited by ansible/ansible#76262.
ISSUE TYPE

Docs Pull Request

COMPONENT NAME
some modules

Reviewed-by: Brian Scholer <None>
Reviewed-by: Mark Chappell <None>
Reviewed-by: None <None>

ec2_elb_info.py

@@ -24,7 +24,7 @@
 deprecated:
   removed_in: 3.0.0
   why: The ec2_elb_info is based upon a deprecated version of the AWS SDK.
-  alternative: Use M(elb_classic_lb_info).
+  alternative: Use M(community.aws.elb_classic_lb_info).
 short_description: Gather information about EC2 Elastic Load Balancers in AWS
 description:
     - Gather information about EC2 Elastic Load Balancers in AWS

iam.py

@@ -13,7 +13,9 @@
 deprecated:
   removed_in: 3.0.0
   why: The iam module is based upon a deprecated version of the AWS SDK.
-  alternative: Use M(iam_user), M(iam_group), M(iam_role), M(iam_policy) and M(iam_managed_policy) modules.
+  alternative: >-
+    Use M(community.aws.iam_user), M(community.aws.iam_group), M(community.aws.iam_role), M(community.aws.iam_policy)
+    and M(community.aws.iam_managed_policy) modules.
 
 short_description: Manage IAM users, groups, roles and keys
 description:

rds.py

@@ -13,7 +13,7 @@
 deprecated:
   removed_in: 3.0.0
   why: The rds module is based upon a deprecated version of the AWS SDK.
-  alternative: Use M(rds_instance), M(rds_instance_info), and M(rds_snapshot).
+  alternative: Use M(community.aws.rds_instance), M(community.aws.rds_instance_info), and M(community.aws.rds_instance_snapshot).
 short_description: create, delete, or modify Amazon rds instances, rds snapshots, and related facts
 description:
     - Creates, deletes, or modifies rds resources.