Fixed % formatting in some printf-style strings.

FossilOrigin-Name: f96add898f096cfc1e435c625ce74093d790b3c7
diff --git a/tool/lemon.c b/tool/lemon.c
index 49f3f31..d7e4530 100644
--- a/tool/lemon.c
+++ b/tool/lemon.c
@@ -2281,7 +2281,7 @@
     case WAITING_FOR_DESTRUCTOR_SYMBOL:
       if( !isalpha(x[0]) ){
         ErrorMsg(psp->filename,psp->tokenlineno,
-          "Symbol name missing after %destructor keyword");
+          "Symbol name missing after %%destructor keyword");
         psp->errorcnt++;
         psp->state = RESYNC_AFTER_DECL_ERROR;
       }else{
@@ -2295,7 +2295,7 @@
     case WAITING_FOR_DATATYPE_SYMBOL:
       if( !isalpha(x[0]) ){
         ErrorMsg(psp->filename,psp->tokenlineno,
-          "Symbol name missing after %type keyword");
+          "Symbol name missing after %%type keyword");
         psp->errorcnt++;
         psp->state = RESYNC_AFTER_DECL_ERROR;
       }else{