ComptimeStringMap: return a regular struct and optimize

this patch renames ComptimeStringMap to StaticStringMap, makes it
accept only a single type parameter, and return a known struct type
instead of an anonymous struct.  initial motivation for these changes
was to reduce the 'very long type names' issue described here
https://github.com/ziglang/zig/pull/19682.

this breaks the previous API.  users will now need to write:
`const map = std.StaticStringMap(T).initComptime(kvs_list);`

* move `kvs_list` param from type param to an `initComptime()` param
* new public methods
  * `keys()`, `values()` helpers
  * `init(allocator)`, `deinit(allocator)` for runtime data
  * `getLongestPrefix(str)`, `getLongestPrefixIndex(str)` - i'm not sure
     these belong but have left in for now incase they are deemed useful
* performance notes:
  * i posted some benchmarking results here:
    https://github.com/travisstaloch/comptime-string-map-revised/issues/1
  * i noticed a speedup reducing the size of the struct from 48 to 32
    bytes and thus use u32s instead of usize for all length fields
  * i noticed speedup storing KVs as a struct of arrays
  * latest benchmark shows these wall_time improvements for
    debug/safe/small/fast builds: -6.6% / -10.2% / -19.1% / -8.9%. full
    output in link above.

1 files changed, 1 insertions, 1 deletions

diff --git a/tools/generate_linux_syscalls.zig b/tools/generate_linux_syscalls.zig
index 8c066f749e..ba368e1f0b 100644
--- a/tools/generate_linux_syscalls.zig
+++ b/tools/generate_linux_syscalls.zig
@@ -9,7 +9,7 @@ const fmt = std.fmt;
 const zig = std.zig;
 const fs = std.fs;
 
-const stdlib_renames = std.ComptimeStringMap([]const u8, .{
+const stdlib_renames = std.StaticStringMap([]const u8).initComptime(.{
     // Most 64-bit archs.
     .{ "newfstatat", "fstatat64" },
     // POWER.