After b1d708dd16, the Toolchain directory
was removed from the repository. Some documentation and scripts still
referenced it, so this commit removes those references. The only
remaining references are in the gitignore file, to prevent bisections
from being polluted by the presence of a Toolchain directory in the
working copy.
The "SerenityOS DSL Syntax Highlight" extension has been de-listed
from both the VS Code Marketplace and Open VSX. Remove the broken
section from the documentation to prevent confusion.
The reason for this change is that CMake/vcpkg are unable to detect a
change to VCPKG_LIBRARY_LINKAGE. So when we switch to dynamic builds,
the switch would be non-functional, and every developer would have to
remove their Build and vcpkg cache directories manually. By changing
these directories, vcpkg is able to detect it must rebuild.
