overview: update code snippet and libc list

Author: andrewrk

content/en-US/learn/overview.smd

@@ -346,6 +346,7 @@ You can find the available libc targets with `zig targets`:
   "aarch64-freebsd-none",
   "aarch64-linux-gnu",
   "aarch64-linux-musl",
+  "aarch64-maccatalyst-none",
   "aarch64-macos-none",
   "aarch64-netbsd-none",
   "aarch64-windows-gnu",
@@ -382,7 +383,6 @@ You can find the available libc targets with `zig targets`:
   "mips64el-linux-gnuabin32",
   "mips64el-linux-muslabi64",
   "mips64el-linux-muslabin32",
-  "powerpc-freebsd-eabihf",
   "powerpc-linux-gnueabi",
   "powerpc-linux-gnueabihf",
   "powerpc-linux-musleabi",
@@ -417,6 +417,7 @@ You can find the available libc targets with `zig targets`:
   "x86_64-linux-gnux32",
   "x86_64-linux-musl",
   "x86_64-linux-muslx32",
+  "x86_64-maccatalyst-none",
   "x86_64-macos-none",
   "x86_64-netbsd-none",
   "x86_64-windows-gnu",

zig-code/features/19-generics.zig

@@ -9,7 +9,7 @@ fn List(comptime T: type) type {
 
 pub fn main() void {
     var buffer: [10]i32 = undefined;
-    var list = List(i32){
+    var list: List(i32) = .{
         .items = &buffer,
         .len = 0,
     };