Make sure branches have proper .x suffix so that they can be parsed properly

src/Composer/Package/Loader/ArrayLoader.php

@@ -151,7 +151,7 @@ class ArrayLoader
                 }
 
                 $package->setAlias($validatedTargetBranch);
-                $package->setPrettyAlias($targetBranch);
+                $package->setPrettyAlias(preg_replace('{(\.9{7})+}', '.x', $validatedTargetBranch));
                 break;
             }
         }

src/Composer/Repository/VcsRepository.php

@@ -200,7 +200,7 @@ class VcsRepository extends ArrayRepository
             if ('dev-' === substr($parsedBranch, 0, 4) || '9999999-dev' === $parsedBranch) {
                 $data['version'] = 'dev-' . $data['version'];
             } else {
-                $data['version'] = $data['version'] . '-dev';
+                $data['version'] = preg_replace('{(\.9{7})+}', '.x', $parsedBranch);
             }
 
             if ($verbose) {