Move the autocommand into the ftplugin, making it buffer local.
This also has the nice benefit of removing the need for the plugin file altogether, so now the zig.vim plugin does not execute any code unless a Zig buffer is explicitly opened (which is a good pattern for filetype plugins). This also clears the way for the Zig runtime files to be upstreamed to Vim itself (all filetype specific code needs to be in an ftplugin).
Move the autocommand into the ftplugin, making it buffer local.
This also has the nice benefit of removing the need for the plugin file altogether, so now the zig.vim plugin does not execute any code unless a Zig buffer is explicitly opened (which is a good pattern for filetype plugins). This also clears the way for the Zig runtime files to be upstreamed to Vim itself (all filetype specific code needs to be in an ftplugin).