Nvim: switch F6 to ClangdSwitchSourceHeader, update plugin configs

.config/nvim/init.vim

@@ -56,7 +56,7 @@ Plug 'quangnguyen30192/cmp-nvim-ultisnips'
 " Files switch, jump and grep-like tools {{{
 Plug 'kyazdani42/nvim-web-devicons' " for file icons
 Plug 'kyazdani42/nvim-tree.lua'
-Plug 'derekwyatt/vim-fswitch'
+"Plug 'derekwyatt/vim-fswitch'
 "Plug 'junegunn/fzf' | Plug 'junegunn/fzf.vim'
 Plug 'nvim-lua/popup.nvim'
 Plug 'nvim-lua/plenary.nvim'
@@ -93,7 +93,6 @@ Plug 'junegunn/goyo.vim'
 Plug 'lukas-reineke/virt-column.nvim'
 "Plug 'glacambre/firenvim'
 "Plug 'JMcKiern/vim-shoot'
-Plug 'mrjones2014/legendary.nvim'
 Plug 'protex/better-digraphs.nvim'
 " }}}