Fix math incorrect parenthesis error on missing term

src/builtin_math.cpp

@@ -147,6 +147,8 @@ static const wchar_t *math_describe_error(te_error_t &error) {
             return _(L"Too many arguments");
         case TE_ERROR_MISSING_OPERATOR:
             return _(L"Missing operator");
+        case TE_ERROR_UNEXPECTED_TOKEN:
+            return _(L"Unexpected token");
         case TE_ERROR_UNKNOWN:
             return _(L"Expression is bogus");
         default:

src/tinyexpr.cpp

@@ -367,7 +367,7 @@ static te_expr *base(state *s) {
                 }
                 if (s->type == TOK_CLOSE && i == arity - 1) {
                     next_token(s);
-                } else if (s->type != TOK_ERROR || s->error == TE_ERROR_UNKNOWN) {
+                } else if (s->type != TOK_ERROR || s->error == TE_ERROR_UNEXPECTED_TOKEN) {
                     s->type = TOK_ERROR;
                     s->error = i < arity ? TE_ERROR_TOO_FEW_ARGS : TE_ERROR_TOO_MANY_ARGS;
                 }
@@ -403,7 +403,7 @@ static te_expr *base(state *s) {
         default:
             ret = new_expr(0, 0);
             s->type = TOK_ERROR;
-            s->error = TE_ERROR_UNKNOWN;
+            s->error = TE_ERROR_UNEXPECTED_TOKEN;
             ret->value = NAN;
             break;
     }

src/tinyexpr.h

@@ -35,7 +35,8 @@ typedef enum {
     TE_ERROR_TOO_FEW_ARGS = 4,
     TE_ERROR_TOO_MANY_ARGS = 5,
     TE_ERROR_MISSING_OPERATOR = 6,
-    TE_ERROR_UNKNOWN = 7
+    TE_ERROR_UNEXPECTED_TOKEN = 7,
+    TE_ERROR_UNKNOWN = 8
 } te_error_type_t;
 
 typedef struct te_error_t {

tests/checks/math.fish

@@ -91,7 +91,7 @@ not math 'ncr(1)'
 # CHECKERR: 'ncr(1)'
 # CHECKERR:       ^
 not math 'max()'
-# CHECKERR: math: Error: Expression is bogus
+# CHECKERR: math: Error: Unexpected token
 # CHECKERR: 'max()'
 # CHECKERR:    ^
 not math 'sin()'