Add VS2015 + char literals in GENERATE issue to known-limitations

Closes #2207

docs/limitations.md

@@ -104,6 +104,20 @@ Both of these solutions have their problems, but should let you wring parallelis
 ## 3rd party bugs
 This section outlines known bugs in 3rd party components (this means compilers, standard libraries, standard runtimes).
 
+### Visual Studio 2015 -- `GENERATE` does not compile if it would deduce char array
+
+VS 2015 refuses to compile `GENERATE` statements that would deduce to a
+char array with known size, e.g. this:
+```cpp
+TEST_CASE("Deducing string lit") {
+    auto param = GENERATE("start", "stop");
+}
+```
+
+A workaround for this is to use the `as` helper and force deduction of
+either a `char const*` or a `std::string`.
+
+
 ### Visual Studio 2017 -- raw string literal in assert fails to compile
 There is a known bug in Visual Studio 2017 (VC 15), that causes compilation error when preprocessor attempts to stringize a raw string literal (`#` preprocessor is applied to it). This snippet is sufficient to trigger the compilation error:
 ```cpp