Fix path typo in Ubuntu Focal dependency install script. (#374)

components/core/tools/scripts/lib_install/ubuntu-focal/install-prebuilt-packages.sh

@@ -31,7 +31,7 @@ DEBIAN_FRONTEND=noninteractive apt-get install --no-install-recommends -y \
 # NOTE: We use a low priority to avoid affecting the prioritization of any existing alternatives
 # on the user's system.
 update-alternatives --install /usr/bin/cc cc /usr/bin/gcc-10 0 \
-  --slave /usr/share/mna/man1/cc.1.gz cc.1.gz /usr/share/man/man1/gcc.1.gz
+  --slave /usr/share/man/man1/cc.1.gz cc.1.gz /usr/share/man/man1/gcc.1.gz
 update-alternatives --install /usr/bin/c++ c++ /usr/bin/g++-10 0 \
-  --slave /usr/share/mna/man1/c++.1.gz c++.1.gz /usr/share/man/man1/g++.1.gz
+  --slave /usr/share/man/man1/c++.1.gz c++.1.gz /usr/share/man/man1/g++.1.gz
 update-alternatives --install /lib/cpp cpp /usr/bin/cpp-10 0