bumping libdeflate/small/utfcpp to newer versions (#6709)

* bumping small from 0.2.0 to 0.2.1
bumping libdeflate from 1.18 to 1.19
bumping utfcpp from 3.2.1 to 4.0.5

* rolling back `small` to allow building on NetBSD/amd64.

* keeping submodules on Transmission forks

* bumping `small` to allow building on NetBSD/amd64.

.gitmodules

@@ -1,58 +1,64 @@
 [submodule "third-party/dht"]
 	path = third-party/dht
-	url = https://github.com/transmission/dht
+	url = https://github.com/transmission/dht.git
 	branch = post-0.27-transmission
 [submodule "third-party/libb64"]
 	path = third-party/libb64
-	url = https://github.com/transmission/libb64
+	url = https://github.com/transmission/libb64.git
 	branch = post-1.2.1-transmission
 [submodule "third-party/libevent"]
 	path = third-party/libevent
-	url = https://github.com/transmission/libevent
+	url = https://github.com/transmission/libevent.git
 	branch = post-2.0.22-transmission
 [submodule "third-party/libnatpmp"]
 	path = third-party/libnatpmp
-	url = https://github.com/transmission/libnatpmp
+	url = https://github.com/transmission/libnatpmp.git
 	branch = post-20151025-transmission
 [submodule "third-party/libutp"]
 	path = third-party/libutp
-	url = https://github.com/transmission/libutp
+	url = https://github.com/transmission/libutp.git
 	branch = post-3.4-transmission
 [submodule "third-party/miniupnp"]
 	path = third-party/miniupnp
+	# synced with https://github.com/miniupnp/miniupnp.git
 	url = https://github.com/transmission/miniupnp.git
 [submodule "third-party/googletest"]
 	path = third-party/googletest
 	url = https://github.com/google/googletest.git
 [submodule "third-party/utfcpp"]
-	branch = post-3.2.1-transmission
 	path = third-party/utfcpp
-	url = https://github.com/transmission/utfcpp
+	# synced with https://github.com/nemtrif/utfcpp.git
+	url = https://github.com/transmission/utfcpp.git
 [submodule "third-party/libdeflate"]
 	path = third-party/libdeflate
-	url = https://github.com/transmission/libdeflate
-	branch = v1.17.x
+	# synced with https://github.com/ebiggers/libdeflate.git
+	url = https://github.com/transmission/libdeflate.git
 [submodule "third-party/libpsl"]
 	path = third-party/libpsl
 	url = https://github.com/transmission/libpsl.git
 	branch = post-3.0.0-transmission
 [submodule "third-party/fmt"]
 	path = third-party/fmt
+	# synced with https://github.com/fmtlib/fmt.git
 	url = https://github.com/transmission/fmt.git
-	branch = 9-x-y
 [submodule "third-party/fast_float"]
 	path = third-party/fast_float
-	url = https://github.com/transmission/fast_float
+	# synced with https://github.com/fastfloat/fast_float.git
+	url = https://github.com/transmission/fast_float.git
 [submodule "third-party/wide-integer"]
 	path = third-party/wide-integer
-	url = https://github.com/transmission/wide-integer
+	# synced with https://github.com/ckormanyos/wide-integer.git
+	url = https://github.com/transmission/wide-integer.git
 [submodule "third-party/small"]
 	path = third-party/small
+	# synced with https://github.com/alandefreitas/small.git
 	url = https://github.com/transmission/small.git
 [submodule "third-party/rapidjson"]
 	path = third-party/rapidjson
+	# synced with https://github.com/Tencent/rapidjson.git
 	url = https://github.com/transmission/rapidjson.git
 	fetchRecurseSubmodules = false
 [submodule "third-party/rpavlik-cmake-modules"]
 	path = third-party/rpavlik-cmake-modules
+	# synced with https://github.com/rpavlik/cmake-modules.git
 	url = https://github.com/transmission/rpavlik-cmake-modules.git