chore(rc,profile,aliases,completion,libs,functions): Remove shebangs from sourced files

These files are always sourced (never executed directly), so the
#!/bin/bash shebang is inert and misleading. Drop it consistently
across rc.d/*, profile.d/*, and aliases.d/*.

profile.d/path

@@ -1,5 +1,3 @@
-#!/bin/bash
-
 # Customize PATH
 if [ -d $HOME/.bin ] ; then export PATH=$PATH:$HOME/.bin ; fi
 if [ -d $HOME/.local/bin ] ; then export PATH=$PATH:$HOME/.local/bin ; fi