recoll: fix generation of string lists

The updated implementation will quote string lists as per the
description at

  https://www.lesbonscomptes.com/recoll/usermanual/#RCL.INSTALL.CONFIG

Fixes #3732

modules/services/recoll.nix

@@ -10,13 +10,14 @@ let
   # see the example configuration from the package (i.e.,
   # `$out/share/recoll/examples/recoll.conf`).
   mkRecollConfKeyValue = generators.mkKeyValueDefault {
-    mkValueString = v:
+    mkValueString = let mkQuoted = v: ''"${escape [ ''"'' ] v}"'';
+    in v:
     if v == true then
       "1"
     else if v == false then
       "0"
     else if isList v then
-        concatStringsSep " " v
+      concatMapStringsSep " " mkQuoted v
     else
       generators.mkValueStringDefault { } v;
   } " = ";

tests/modules/services/recoll/basic-configuration.conf

@@ -1,16 +1,18 @@
+dbdir = ~/.cache/recoll/xapiandb
+
 nocjk = 0
 
-skippedNames+ = node_modules
+skippedNames+ = "node_modules"
 
-topdirs = ~/Downloads ~/Documents ~/library
+topdirs = "~/Downloads" "~/Documents" "~/library" "~/\"cool\" files"
 
 underscoresasletter = 1
 
 [~/library/projects]
-skippedNames+ = .editorconfig .gitignore result flake.lock go.sum
+skippedNames+ = ".editorconfig" ".gitignore" "result" "flake.lock" "go.sum"
 
 [~/library/projects/software]
-skippedNames+ = target result
+skippedNames+ = "target" "result"
 
 [~/what-is-this-project]
-skippedNames+ = whoa-there
+skippedNames+ = "whoa-there"

tests/modules/services/recoll/basic-configuration.nix

@@ -6,7 +6,8 @@
     package = config.lib.test.mkStubPackage { };
     configDir = "${config.xdg.configHome}/recoll";
     settings = {
-      topdirs = [ "~/Downloads" "~/Documents" "~/library" ];
+      dbdir = "~/.cache/recoll/xapiandb";
+      topdirs = [ "~/Downloads" "~/Documents" "~/library" ''~/"cool" files'' ];
       "skippedNames+" = [ "node_modules" ];
       underscoresasletter = true;
       nocjk = false;

tests/modules/services/recoll/config-format-order.conf

@@ -4,7 +4,7 @@ d = 0
 
 e = This should be the second to the last non-attrset value in the config.
 
-g = This is coming from a list
+g = "This" "is" "coming" "from" "a" "list"
 
 [a]
 foo = bar
@@ -18,7 +18,7 @@ b = 53
 a = This should be second to the last for the attribute names with an attrset.
 b = 3193
 c = 0
-d = Hello there
+d = "Hello" "there"
 
 [foo]
 bar = This should be the last attribute with an attrset.