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, 2 insertions, 2 deletions

diff --git a/lib/std/meta.zig b/lib/std/meta.zig
index 3ad2c2de13..0dcbe64548 100644
--- a/lib/std/meta.zig
+++ b/lib/std/meta.zig
@@ -19,7 +19,7 @@ pub const isTag = @compileError("deprecated; use 'tagged_value == @field(E, tag_
 
 /// Returns the variant of an enum type, `T`, which is named `str`, or `null` if no such variant exists.
 pub fn stringToEnum(comptime T: type, str: []const u8) ?T {
-    // Using ComptimeStringMap here is more performant, but it will start to take too
+    // Using StaticStringMap here is more performant, but it will start to take too
     // long to compile if the enum is large enough, due to the current limits of comptime
     // performance when doing things like constructing lookup maps at comptime.
     // TODO The '100' here is arbitrary and should be increased when possible:
@@ -34,7 +34,7 @@ pub fn stringToEnum(comptime T: type, str: []const u8) ?T {
             }
             break :build_kvs kvs_array[0..];
         };
-        const map = std.ComptimeStringMap(T, kvs);
+        const map = std.StaticStringMap(T).initComptime(kvs);
         return map.get(str);
     } else {
         inline for (@typeInfo(T).Enum.fields) |enumField| {