Add cppman

init.vim

@@ -298,7 +298,7 @@ nmap <silent> gi <Plug>(coc-implementation)
 nmap <silent> gr <Plug>(coc-references)
 
 " Use K to show documentation in preview window
-nnoremap <silent> K :call <SID>show_documentation()<CR>
+nnoremap <silent> H :call <SID>show_documentation()<CR>
 
 function! s:show_documentation()
   if (index(['vim','help'], &filetype) >= 0)

vim/ftplugin/cpp.vim

@@ -5,3 +5,6 @@ let g:ale_cpp_clangtidy_checks = ['*,-fuchsia*']
 
 setlocal shiftwidth=2
 setlocal tabstop=2
+
+" Documentation inside vim
+autocmd FileType cpp set keywordprg=cppman