treewide: Fix invalid string escapes

(cherry picked from commit 591861f)

pkgs/build-support/trivial-builders/default.nix

@@ -719,7 +719,7 @@ rec {
           (name: value:
             {
               inherit value;
-              name = lib.head (builtins.match "${builtins.storeDir}/[${nixHashChars}]+-(.*)\.drv" name);
+              name = lib.head (builtins.match "${builtins.storeDir}/[${nixHashChars}]+-(.*)\\.drv" name);
             })
           derivations;
       # The syntax of output paths differs between outputs named `out`

pkgs/pkgs-lib/formats/hocon/test/comprehensive/default.nix

@@ -37,7 +37,7 @@ let
         "b"
       ]
     ];
-    nasty_string = "\"@\n\\\t^*\b\f\n\0\";'''$";
+    nasty_string = "\"@\n\\\t^*bf\n0\";'''$";
 
     "misc attrs" = {
       x = 1;

pkgs/pkgs-lib/formats/java-properties/test/default.nix

@@ -73,7 +73,7 @@ stdenv.mkDerivation {
   );
 
   src = lib.sourceByRegex ./. [
-    ".*\.java"
+    ".*\\.java"
   ];
   # On Linux, this can be C.UTF-8, but darwin + zulu requires en_US.UTF-8
   LANG = "en_US.UTF-8";

pkgs/pkgs-lib/formats/libconfig/test/comprehensive/default.nix

@@ -58,7 +58,7 @@ let
         1
       ])
     ];
-    nasty_string = "\"@\n\\\t^*\b\f\n\0\";'''$";
+    nasty_string = "\"@\n\\\t^*bf\n0\";'''$";
 
     weirderTypes = {
       _includes = [ include_file ];