`modernize-use-trailing-return-type` reports underlying type in fix-it for lamdba

[firewave]

#include <algorithm>
#include <cstddef>

void f()
{
    auto val = [](size_t m) {
        size_t a = 0;
        return std::max(m, a);
    };
}

<source>:6:16: warning: use a trailing return type for this lambda [modernize-use-trailing-return-type]
    6 |     auto val = [](size_t m) {
      |                ^
      |                             -> unsigned long

https://godbolt.org/z/9K4M7Mz8E

It should be reporting size_t instead. It seems to be related to the template call involved.

[llvmbot]

@llvm/issue-subscribers-clang-tidy

Author: Oliver Stöneberg (firewave)

```cpp #include <algorithm> #include <cstddef>

void f()
{
auto val = [](size_t m) {
size_t a = 0;
return std::max(m, a);
};
}

<source>:6:16: warning: use a trailing return type for this lambda [modernize-use-trailing-return-type]
6 | auto val = [](size_t m) {
| ^
| -> unsigned long

https://godbolt.org/z/9K4M7Mz8E

It should be reporting `size_t` instead. It seems to be related to the template call involved.
</details>

[llvmbot]

@llvm/issue-subscribers-bug

Author: Oliver Stöneberg (firewave)

```cpp #include <algorithm> #include <cstddef>

void f()
{
auto val = [](size_t m) {
size_t a = 0;
return std::max(m, a);
};
}

<source>:6:16: warning: use a trailing return type for this lambda [modernize-use-trailing-return-type]
6 | auto val = [](size_t m) {
| ^
| -> unsigned long

https://godbolt.org/z/9K4M7Mz8E

It should be reporting `size_t` instead. It seems to be related to the template call involved.
</details>

[vbvictor]

Seems like a wrong printing policy here:

llvm-project/clang-tools-extra/clang-tidy/modernize/UseTrailingReturnTypeCheck.cpp

Line 636 in 549bc55

ReturnType.getAsString(Result.Context->getPrintingPolicy()));

Setting PrintAsCanonical to false doesn't help immediately, probably when we use Lambda->getCallOperator() we get CXXConversionDecl that thinks it has unsigned long as a return type.

[firewave]

The same is reported with libc++: https://godbolt.org/z/Tda4vq17d