gir: Gracefully handle missing .gir files

They aren't required for compilation anymore, and not being able to show
documentation on hover is probably not worth crashing the language
server over.

blueprintcompiler/gir.py

@@ -214,9 +214,14 @@ class GirNode:
         if self.signature:
             sections.append("```\n" + self.signature + "\n```")
 
+        try:
             el = self.xml.get_elements("doc")
             if len(el) == 1:
                 sections.append(el[0].cdata.strip())
+        except:
+            # Not a huge deal, but if you want docs in the language server you
+            # should ensure .gir files are installed
+            pass
 
         return "\n\n---\n\n".join(sections)