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/*.

libs/xml.bash

@@ -1,4 +1,2 @@
-#!/bin/bash
-
 function prettyxml () { sed -e 's,>,>\n,g'; }