Error: don't use edit notation in observables

[hmedina]

Cryptic error:
1/1 File "term/pattern_compiler.ml", line 593, characters 20-26: Assertion failed

In the GUI, the following MWE produces the cryptic error:

%agent: Bob(a,b)
%obs: 'foo' |Bob(a[./1]), Bob(b[./1])|

The GUI's parser does not flag the error on the observable line, which is using edit notation inside an observable. Instead it throws a rather cryptic error, which points to a function about some assertion related to unary rules and the mixture failing.

• The GUI/IDE should catch this syntax error.