context: stop catching TypeError when converting hex nodeid to binary

It has been a programming error to pass a 40-character string that is
not a hex nodeid since 8b86acc7aa64 (context: drop support for looking
up context by ambiguous changeid (API), 2018-04-28), so we can just
let it raise a TypeError.

Differential Revision: https://phab.mercurial-scm.org/D4807

mercurial/context.py

@@ -435,7 +435,7 b' class changectx(basectx):'
                     return
                 except error.FilteredLookupError:
                     raise
-                except (TypeError, LookupError):
+                except LookupError:
                     pass
             else:
                 raise error.ProgrammingError(