allow omitting stmts using finally as post expr blocks; make it consistent with else, except etc. (#21361)

allow omitting stmts using `finally` as post expr blocks

compiler/parser.nim

@@ -1496,7 +1496,7 @@ proc postExprBlocks(p: var Parser, x: PNode): PNode =
     result = makeCall(result)
     getTok(p)
     skipComment(p, result)
-    if p.tok.tokType notin {tkOf, tkElif, tkElse, tkExcept}:
+    if p.tok.tokType notin {tkOf, tkElif, tkElse, tkExcept, tkFinally}:
       var stmtList = newNodeP(nkStmtList, p)
       stmtList.add parseStmt(p)
       # to keep backwards compatibility (see tests/vm/tstringnil)

tests/parser/tpostexprblocks.nim

@@ -498,6 +498,13 @@ StmtList
         StmtList
           DiscardStmt
             Empty
+
+  Call
+    Ident "foo"
+    Finally
+      StmtList
+        DiscardStmt
+          Empty
 '''
 """
 
@@ -655,3 +662,7 @@ dumpTree:
     discard
   finally:
     discard
+
+  foo:
+  finally:
+    discard