Minor updates for Ruby 3.x.

FossilOrigin-Name: 792a95e73dbfb858dbbd56b1140c2ddf6bc3afb558e65cc665f30fd6db6833e1

.ruby-version

@@ -1 +1 @@
-2.7
+3.1

ext/mdbx_ext/database.c

@@ -860,7 +860,7 @@ static VALUE rmdbx_init_copy( VALUE copy, VALUE orig )
 void
 rmdbx_init_database()
 {
-	rmdbx_cDatabase = rb_define_class_under( rmdbx_mMDBX, "Database", rb_cData );
+	rmdbx_cDatabase = rb_define_class_under( rmdbx_mMDBX, "Database", rb_cObject );
 
 #ifdef FOR_RDOC
 	rmdbx_mMDBX = rb_define_module( "MDBX" );

lib/mdbx/database.rb

@@ -85,7 +85,7 @@ class MDBX::Database
 	###
 	### [:no_threadlocal]
 	###   Parallelize read-only transactions across threads.  Writes are
-	###   always thread local. (See MDBX documentatoin for details.)
+	###   always thread local. (See MDBX documentation for details.)
 	###
 	### [:readonly]
 	###   Reject any write attempts while using this database handle.
@@ -364,7 +364,6 @@ class MDBX::Database
 	protected
 	#########
 
-
 	### Safely serialize a value, closing any open transaction and re-raising
 	### if necessary.
 	###
@@ -391,7 +390,6 @@ class MDBX::Database
 	end
 
 
-
 	### Yield and return the block, opening a snapshot first if
 	### there isn't already a transaction in progress.  Closes
 	### the snapshot if this method opened it.

spec/mdbx/database_spec.rb

@@ -71,8 +71,7 @@ RSpec.describe( MDBX::Database ) do
 			# here for behavior.
 			expect {
 				described_class.open( TEST_DATABASE.to_s )
-			}.
-			to raise_exception( MDBX::DatabaseError, /environment is already used/ )
+            }.to raise_exception( MDBX::DatabaseError, /resource \w+ unavailable/i )
 		end
 	end