treewide: fix double quoted strings in meta.description

Signed-off-by: Ben Siraphob <bensiraphob@gmail.com>

nixos/modules/services/web-apps/dokuwiki.nix

@@ -336,7 +336,7 @@ in
         locations."/" = {
           priority = 1;
           index = "doku.php";
-          extraConfig = ''try_files $uri $uri/ @dokuwiki;'';
+          extraConfig = "try_files $uri $uri/ @dokuwiki;";
         };
 
         locations."@dokuwiki" = {

nixos/modules/services/web-apps/keycloak.nix

@@ -565,7 +565,7 @@ in
         assertions = [
           {
             assertion = (cfg.databaseUseSSL && cfg.databaseType == "postgresql") -> (cfg.databaseCaCert != null);
-            message = ''A CA certificate must be specified (in 'services.keycloak.databaseCaCert') when PostgreSQL is used with SSL'';
+            message = "A CA certificate must be specified (in 'services.keycloak.databaseCaCert') when PostgreSQL is used with SSL";
           }
         ];
 

nixos/modules/services/web-apps/moodle.nix

@@ -84,7 +84,7 @@ in
       type = mkOption {
         type = types.enum [ "mysql" "pgsql" ];
         default = "mysql";
-        description = ''Database engine to use.'';
+        description = "Database engine to use.";
       };
 
       host = mkOption {