Fix -Wpedantic violations when included in C++

[robinlinden]

This fixes a bunch of error: extra ';' [-Werror=pedantic] issues.

To test this without the codebase where I was using zenoh-pico, I added a C++ "example" where I just included zenoh-pico.h and printed the version used like so:

examples/CMakeLists.txt

+if(ZENOH_CXX_EXAMPLES)
+    enable_language(CXX)
+    add_compile_options(-Wall -Wextra -Werror -Wpedantic)
+    add_example(compilation cpp/compilation.cpp)
+endif()

examples/cpp/compilation.cpp

#include <zenoh-pico.h>

#include <iostream>

int main() {
    std::cout << "Compiled with Zenoh-Pico version: " << ZENOH_PICO << '\n';
}

[github-actions]

PR missing one of the required labels: {'breaking-change', 'enhancement', 'bug', 'new feature', 'internal', 'dependencies', 'documentation'}

[github-actions]

PR missing one of the required labels: {'documentation', 'breaking-change', 'dependencies', 'enhancement', 'bug', 'internal', 'new feature'}

[github-actions]

PR missing one of the required labels: {'enhancement', 'breaking-change', 'new feature', 'bug', 'documentation', 'dependencies', 'internal'}