vim:nvim-man: Source vimrc and fix weird input

Remove `NORC` as settings like `smartcase` or my color scheme are things
I do not want to miss and the startup time delta feels negligible.

Fix a weird issue with presumably the line breaks and tabs in the
command string that would make vim send key inputs when starting through
`nvim-man`. This would lead to tmux switching panes and tmux-resurrect
failing to recover panes with vim opened like this.

.config/zsh/zshrc.d/40-functions.zsh

@@ -401,13 +401,7 @@ nvim-man() {
 		command man -w "$1" >/dev/null || return
 
 		# $MANPAGER would do the trick too but lines would be hard-wrapped.
-		nvim -u NORC +"
+		nvim +"Man $1 | only | set scrolloff=999 | normal M"
-			runtime! plugin/man.vim |
-			Man $1 |
-			only |
-			set scrolloff=999 |
-			normal M
-		"
 	else
 		command man "$@"
 	fi