Remove SC1091 disable directives

These were added before .shellcheckrc was created in my dotfiles. Now
that said rc file has been added, this no longer needs to be disabled
inline.

src/.bashrc

@@ -5,7 +5,6 @@
 
 # source global definitions (if any)
 if [ -f /etc/bashrc ]; then
-	# shellcheck disable=SC1091
 	. /etc/bashrc
 fi
 
@@ -566,7 +565,6 @@ function .9 {
 # programmable completion
 # source available completion file
 if [ -f /etc/bash_completion ]; then
-	# shellcheck disable=SC1091
 	. /etc/bash_completion
 fi