fish: upstream patch to fix tests after pcre2 update

pkgs/shells/fish/default.nix

@@ -1,6 +1,7 @@
 { stdenv
 , lib
 , fetchurl
+, fetchpatch
 , coreutils
 , which
 , gnused
@@ -146,6 +147,8 @@ let
       sha256 = "sha256-tbTuGlJpdiy76ZOkvWUH5nXkEAzpu+hCFKXusrGfrok=";
     };
 
+    patches = [ ./tests-pcre2-update.patch ]; # should be included in >= 3.4
+
     # Fix FHS paths in tests
     postPatch = ''
       # src/fish_tests.cpp

pkgs/shells/fish/tests-pcre2-update.patch

@@ -0,0 +1,7 @@
+Adapted formating to 3.3.1 from
+https://github.com/fish-shell/fish-shell/commit/ec8844d834cc9fe626e9fc326c6f5410341d532a
+--- a/src/fish_tests.cpp
++++ b/src/fish_tests.cpp
+@@ -5726,2 +5725,0 @@
+-        {{L"string", L"match", L"-r", L"(?=ab\\K)", L"ab", 0}, STATUS_CMD_OK, L"\n"},
+-        {{L"string", L"match", L"-r", L"(?=ab\\K)..(?=cd\\K)", L"abcd", 0}, STATUS_CMD_OK, L"\n"},