Fix backticks in PEP 545 language subtag description

Author: m-aciek

peps/pep-0545.rst

@@ -199,7 +199,7 @@ Examples of IETF Language Tags:
 * ``pt-br`` (Portugese as spoken in Brazil),
 * ``pa-guru`` (Punjabi written in Gurmukhi script)
 
-The `script` subtag is used when a language can be written in multiple
+The ``script`` subtag is used when a language can be written in multiple
 writing systems. For example, Punjabi can be written in Gurmukhi (``pa-guru``)
 or Shahmukhi (``pa-arab``).