docs: Fix typos in cdr/

Found via codespell

(cherry picked from commit f221ef9777)

cdr/cdr_beanstalkd.c

@@ -20,7 +20,7 @@
  * \file
  * \brief Asterisk Beanstalkd CDR records.
  *
- * This module requires the beanstalk-client library, avaialble from
+ * This module requires the beanstalk-client library, available from
  * https://github.com/deepfryed/beanstalk-client
  *
  * See also

cdr/cdr_custom.c

@@ -142,7 +142,7 @@ static int custom_log(struct ast_cdr *cdr)
 
 	dummy = ast_dummy_channel_alloc();
 	if (!dummy) {
-		ast_log(LOG_ERROR, "Unable to allocate channel for variable subsitution.\n");
+		ast_log(LOG_ERROR, "Unable to allocate channel for variable substitution.\n");
 		return -1;
 	}
 

cdr/cdr_pgsql.c

@@ -375,7 +375,7 @@ static int pgsql_log(struct ast_cdr *cdr)
 
 						/* If our argument size exceeds our buffer, grow it,
 						 * as PQescapeStringConn() expects the buffer to be
-						 * adequitely sized and does *NOT* do size checking.
+						 * adequately sized and does *NOT* do size checking.
 						 */
 						if (required_size > bufsize) {
 							char *tmpbuf = ast_realloc(escapebuf, required_size);

cdr/cdr_sqlite3_custom.c

@@ -253,7 +253,7 @@ static int write_cdr(struct ast_cdr *cdr)
 
 		dummy = ast_dummy_channel_alloc();
 		if (!dummy) {
-			ast_log(LOG_ERROR, "Unable to allocate channel for variable subsitution.\n");
+			ast_log(LOG_ERROR, "Unable to allocate channel for variable substitution.\n");
 			ast_free(value_string);
 			ast_mutex_unlock(&lock);
 			return 0;