test: added comprehensive tests for in-string & complex nested comments (#2956)

* test: added comprehensive tests for in-string & complex nested comments

* Properly handle error

---------

Co-authored-by: Christoffer Lerno <christoffer.lerno@gmail.com>

test/test_suite/comments/complex_nesting.c3

@@ -0,0 +1,11 @@
+// this test stress-tests the compiler ability to handle complex comments
+
+/* first of all, I wanna say that <* linux *> is the best OS ever!
+   secondly, #!pizza, it's a masterpiece... nothing is better than pizza, // thanks to who cooked it for the first time..
+   I want to rant windows but I'm afraid of it getting mad and not supporting C3.. /* I'll not cause problems, just for this time */
+   I'm forced to use windows for ~4 more months just for my school.. /* this is TERRIBLE guys */
+   #! this line would fail because it's "#!" isn't in the right place (the first two characters of a file).. but since we're already in a comment, it' fine!
+*/
+
+#! this line should raise an error! // #error: a global
+// while this shouldn't!

test/test_suite/comments/instring_comments.c3

@@ -0,0 +1,15 @@
+module instring_comments;
+
+import std;
+
+// this test proves the compiler can handle in string comments reliabely.
+
+fn void test_len() @test {
+    
+    String foo = "Hello, // world!";
+    String bar = "Hello, /* world */!";
+    
+    assert(foo.len == 16);
+    assert(bar.len == 19);
+
+}