add test for declaration errors

tests-pl/invalid_decl1.pl

@@ -0,0 +1 @@
+:- op(10, moin, example).

tests-pl/invalid_decl2.pl

@@ -0,0 +1 @@
+:- op(4000, xfx, example).

tests-pl/invalid_decl3.pl

@@ -0,0 +1 @@
+:- op(5, xfx, example(a,b)).

tests-pl/invalid_decl4.pl

@@ -0,0 +1 @@
+:- op(5, xfx, example, too_many_arguments).

tests-pl/invalid_decl5.pl

@@ -0,0 +1 @@
+:- (test -> set_prolog_flag(double_quotes, codes); true).

tests-pl/invalid_decl6.pl

@@ -0,0 +1 @@
+:- 9001.

tests-pl/invalid_decl7.pl

@@ -0,0 +1 @@
+:- op(10, 42, example).

tests/scryer/cli/src_tests/declaration_errors.md

@@ -0,0 +1,35 @@
+```trycmd
+$ scryer-prolog -f --no-add-history tests-pl/invalid_decl1.pl -g halt
+   error(syntax_error(inconsistent_entry),load/1).
+
+```
+
+```trycmd
+$ scryer-prolog -f --no-add-history tests-pl/invalid_decl2.pl -g halt
+   error(syntax_error(inconsistent_entry),load/1).
+
+```
+
+```trycmd
+$ scryer-prolog -f --no-add-history tests-pl/invalid_decl3.pl -g halt
+   error(syntax_error(inconsistent_entry),load/1).
+
+```
+
+```trycmd
+$ scryer-prolog -f --no-add-history tests-pl/invalid_decl4.pl -g halt
+   error(syntax_error(inconsistent_entry),load/1).
+
+```
+
+```trycmd
+$ scryer-prolog -f --no-add-history tests-pl/invalid_decl5.pl -g halt
+   error(syntax_error(inconsistent_entry),load/1).
+
+```
+
+```trycmd
+$ scryer-prolog -f --no-add-history tests-pl/invalid_decl6.pl -g halt
+   error(syntax_error(inconsistent_entry),load/1).
+
+```

tests/scryer/main.rs

@@ -23,5 +23,6 @@ fn cli_tests() {
         .default_bin_name("scryer-prolog")
         .case("tests/scryer/cli/issues/*.toml")
         .skip("tests/scryer/cli/issues/singleton_warning.toml") // wrong line number
-        .case("tests/scryer/cli/src_tests/*.toml");
+        .case("tests/scryer/cli/src_tests/*.toml")
+        .case("tests/scryer/cli/src_tests/*.md");
 }