Update error message

includes/Checker/Checks/Plugin_Repo/Plugin_Header_Fields_Check.php

@@ -98,14 +98,14 @@ public function run( Check_Result $result ) {
 					6
 				);
 			} else {
-				$valid_chars_count = preg_match_all( '/[a-z0-9-]/i', $plugin_header['Name'] );
+				$valid_chars_count = preg_match_all( '/[a-z0-9]/i', $plugin_header['Name'] );
 
 				if ( intval( $valid_chars_count ) < 5 ) {
 					$this->add_result_error_for_file(
 						$result,
 						sprintf(
 							/* translators: %s: plugin header field */
-							__( 'The "%s" header in the plugin file is not valid. It may only contain latin letters (A-z), numbers, spaces, and hyphens.', 'plugin-check' ),
+							__( 'The "%s" header in the plugin file is not valid. It needs to contain at least 5 latin letters (a-Z) and/or numbers. This is necessary because the initial plugin slug is generated from the name.', 'plugin-check' ),
 							esc_html( $labels['Name'] )
 						),
 						'plugin_header_unsupported_plugin_name',