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/src/link/Wasm/types.zig b/src/link/Wasm/types.zig
index ebb2ddf895..43d3089579 100644
--- a/src/link/Wasm/types.zig
+++ b/src/link/Wasm/types.zig
@@ -244,7 +244,7 @@ pub const Feature = struct {
     }
 };
 
-pub const known_features = std.ComptimeStringMap(Feature.Tag, .{
+pub const known_features = std.StaticStringMap(Feature.Tag).initComptime(.{
     .{ "atomics", .atomics },
     .{ "bulk-memory", .bulk_memory },
     .{ "exception-handling", .exception_handling },