typo in Writing-A-Simple-Cpp-Publisher-And-Subscriber

[woodz-]

fix typos, led to

CMake Error at CMakeLists.txt:22 (find_package):
By not providing "Findrclpp.cmake" in CMAKE_MODULE_PATH this project has
asked CMake to find a package configuration file provided by "rclpp", but
CMake did not find one.

Could not find a package configuration file provided by "rclpp" with any of
the following names:

rclppConfig.cmake
rclpp-config.cmake

Add the installation prefix of "rclpp" to CMAKE_PREFIX_PATH or set
"rclpp_DIR" to a directory containing one of the above files.  If "rclpp"
provides a separate development package or SDK, be sure it has been
installed.

when accidentally declaring

find_package(rclpp REQUIRED)

in CMakeLists.txt of a user defined package

[maryaB-osr]

@Mergifyio backport rolling

[mergify]

Command backport rolling: success

Backports have been created

• #982 typo in Writing-A-Simple-Cpp-Publisher-And-Subscriber (bp #965) has been created for branch rolling