Clarify the difference between (old) `spec_name` and `connection_specification_name`

[ci skip]

activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb

@@ -996,7 +996,7 @@ def checkout_and_verify(c)
     # should use.
     #
     # The ConnectionHandler class is not coupled with the Active models, as it has no knowledge
-    # about the model. The model needs to pass a specification name to the handler,
+    # about the model. The model needs to pass a connection specification name to the handler,
     # in order to look up the correct connection pool.
     class ConnectionHandler
       FINALIZER = lambda { |_| ActiveSupport::ForkTracker.check! }

activerecord/lib/active_record/connection_handling.rb

@@ -209,7 +209,7 @@ def connection
 
     attr_writer :connection_specification_name
 
-    # Return the specification name from the current class or its parent.
+    # Return the connection specification name from the current class or its parent.
     def connection_specification_name
       if !defined?(@connection_specification_name) || @connection_specification_name.nil?
         return self == Base ? Base.name : superclass.connection_specification_name

activerecord/lib/active_record/database_configurations.rb

@@ -30,7 +30,7 @@ def initialize(configurations = {})
     #
     # * <tt>env_name:</tt> The environment name. Defaults to +nil+ which will collect
     #   configs for all environments.
-    # * <tt>name:</tt> The db name name (i.e. primary, animals, etc.). Defaults
+    # * <tt>name:</tt> The db config name (i.e. primary, animals, etc.). Defaults
     #   to +nil+. If no +env_name+ is specified the config for the default env and the
     #   passed +name+ will be returned.
     # * <tt>include_replicas:</tt> Determines whether to include replicas in

activerecord/lib/active_record/database_configurations/hash_config.rb

@@ -17,7 +17,7 @@ class DatabaseConfigurations
     # ==== Options
     #
     # * <tt>:env_name</tt> - The Rails environment, i.e. "development".
-    # * <tt>:name</tt> - The specification name. In a standard two-tier
+    # * <tt>:name</tt> - The db config name. In a standard two-tier
     #   database configuration this will default to "primary". In a multiple
     #   database three-tier database configuration this corresponds to the name
     #   used in the second tier, for example "primary_readonly".

activerecord/lib/active_record/database_configurations/url_config.rb

@@ -20,7 +20,7 @@ class DatabaseConfigurations
     # ==== Options
     #
     # * <tt>:env_name</tt> - The Rails environment, ie "development".
-    # * <tt>:name</tt> - The specification name. In a standard two-tier
+    # * <tt>:name</tt> - The db config name. In a standard two-tier
     #   database configuration this will default to "primary". In a multiple
     #   database three-tier database configuration this corresponds to the name
     #   used in the second tier, for example "primary_readonly".