Python: Allow except* to be written as except *

Turns out, `except*` is actually not a token on its own according to the
Python grammar. This means it's legal to write `except *foo: ...`, which
we previously would consider a syntax error.

To fix it, we simply break up the `except*` into two separate tokens.

python/extractor/tests/parser/exception_groups_new.expected

@@ -1,4 +1,4 @@
-Module: [1, 0] - [22, 0]
+Module: [1, 0] - [27, 0]
   body: [
     Try: [1, 0] - [1, 4]
       body: [
@@ -133,4 +133,24 @@ Module: [1, 0] - [22, 0]
               variable: Variable('v', None)
               ctx: Load
       ]
+    Try: [23, 0] - [23, 4]
+      body: [
+        Pass: [24, 4] - [24, 8]
+      ]
+      orelse: []
+      handlers: [
+        ExceptGroupStmt: [25, 0] - [26, 8]
+          type:
+            Name: [25, 8] - [25, 11]
+              variable: Variable('foo', None)
+              ctx: Load
+          name:
+            Name: [25, 15] - [25, 16]
+              variable: Variable('e', None)
+              ctx: Store
+          body: [
+            Pass: [26, 4] - [26, 8]
+          ]
+      ]
+      finalbody: []
   ]

python/extractor/tests/parser/exception_groups_new.py

@@ -19,3 +19,8 @@ else:
 finally:
     u
     v
+
+try:
+    pass
+except *foo as e:
+    pass

python/extractor/tsg-python/tsp/grammar.js

@@ -309,7 +309,8 @@ module.exports = grammar({
     ),
 
     except_group_clause: $ => seq(
-      'except*',
+      'except',
+      '*',
       seq(
         field('type', $.expression),
         optional(seq(