fix typos in various modules and docsite (#28747)

lib/ansible/modules/cloud/amazon/rds.py

@@ -126,7 +126,7 @@ options:
     description:
       - Port number that the DB instance uses for connections. Used only when command=create or command=replicate.
       - Prior to 2.0 it always defaults to null and the API would use 3306, it had to be set to other DB default values when not using MySql.
-        Starting at 2.0 it automatically defaults to what is expected for each c(db_engine).
+        Starting at 2.0 it automatically defaults to what is expected for each C(db_engine).
     required: false
     default: 3306 for mysql, 1521 for Oracle, 1433 for SQL Server, 5432 for PostgreSQL.
   upgrade:

lib/ansible/modules/network/junos/junos_rpc.py

@@ -22,7 +22,7 @@ short_description: Runs an arbitrary RPC over NetConf on an Juniper JUNOS device
 description:
   - Sends a request to the remote device running JUNOS to execute the
     specified RPC using the NetConf transport.  The reply is then
-    returned to the playbook in the c(xml) key.  If an alternate output
+    returned to the playbook in the C(xml) key.  If an alternate output
     format is requested, the reply is transformed to the requested output.
 extends_documentation_fragment: junos
 options:

lib/ansible/modules/packaging/os/slackpkg.py

@@ -35,7 +35,7 @@ options:
 
     state:
         description:
-            - state of the package, you can use "installed" as an alias for C(present) and removed as one for c(absent).
+            - state of the package, you can use "installed" as an alias for C(present) and removed as one for C(absent).
         choices: [ 'present', 'absent', 'latest' ]
         required: false
         default: present