fix docs

Author: patrickvonplaten

docs/source/en/api/pipelines/wuerstchen.md

@@ -136,6 +136,7 @@ The original codebase, as well as experimental ideas, can be found at [dome272/W
 	- __call__
 
 ## Citation
+```
       @misc{pernias2023wuerstchen,
             title={Wuerstchen: Efficient Pretraining of Text-to-Image Models}, 
             author={Pablo Pernias and Dominic Rampas and Mats L. Richter and Christopher Pal and Marc Aubreville},
@@ -144,4 +145,4 @@ The original codebase, as well as experimental ideas, can be found at [dome272/W
             archivePrefix={arXiv},
             primaryClass={cs.CV}
       }
-
+```