message: Fix static analyzer URLs
diff: - tested with **MSVC**: **2015**, **2017**, **2019** (also in 32 bit mode)
  - per-commit tested on [**travis**](https://travis-ci.org/onqtam/doctest) and [**appveyor**](https://ci.appveyor.com/project/onqtam/doctest) CI services
  - warnings as errors even on the most aggressive warning levels - see [**here**](../../scripts/cmake/common.cmake#L84)
  - - statically analyzed on the CI - [**Cppcheck**](http://cppcheck.sourceforge.net/) / [**Clang-Tidy**](http://oclint.org/) / [**Coverity Scan**](https://scan.coverity.com/) / [**OCLint**](https://scan.coverity.com/) / [**Visual Studio Analyzer**](https://docs.microsoft.com/en-us/visualstudio/code-quality/analyzing-c-cpp-code-quality-by-using-code-analysis)
  + - statically analyzed on the CI - [**Cppcheck**](http://cppcheck.sourceforge.net/) / [**Clang-Tidy**](https://clang.llvm.org/extra/clang-tidy/) / [**Coverity Scan**](https://scan.coverity.com/) / [**OCLint**](http://oclint.org/) / [**Visual Studio Analyzer**](https://docs.microsoft.com/en-us/visualstudio/code-quality/analyzing-c-cpp-code-quality-by-using-code-analysis)
  - all tests have their output compared to reference output of a previous known good run
  - all tests built and ran in **Debug**/**Release** modes
  - all tests ran through **valgrind** under **Linux** (sadly [not under OSX](https://github.com/onqtam/doctest/issues/11))
  