Make awk filters more portable

config/aerc.conf.in

@@ -69,7 +69,7 @@ editor=
 # You can also match on non-mimetypes, by prefixing with the header to match
 # against (non-case-sensitive) and a comma, e.g. subject,text will match a
 # subject which contains "text". Use header,~regex to match against a regex.
-subject,~^\[PATCH=@SHAREDIR@/filters/hldiff
-text/*=@SHAREDIR@/filters/plaintext
+subject,~^\[PATCH=awk -f @SHAREDIR@/filters/hldiff
+text/*=awk -f @SHAREDIR@/filters/plaintext
 #text/html=@SHAREDIR@/filters/html
 #image/*=catimg -w $(tput cols) -

contrib/hldiff

@@ -1,4 +1,3 @@
-#!/usr/bin/env -S awk -f
 # vim: set ft=awk :
 BEGIN {
 	bright = "\x1B[1m"

contrib/plaintext

@@ -1,4 +1,3 @@
-#!/usr/bin/env -S awk -f
 # vim: set ft=awk :
 BEGIN {
 	dim = "\x1B[2m"