Revert "rely on stdin/stdout instead of hardcoded paths"

This reverts commit 2fca0477bc7f3c955daf40a0d4663d63ef3d76a1.

The idea of using stdin and stdout was the integrate it in to the build
script, but since we don't want to do that because it contains an eval,
it just makes it more annoying to use.

src/font/nerd_font_codegen.py

@@ -10,9 +10,9 @@ be safe and not malicious or anything.
 
 import ast
 import math
-import sys
 from collections import defaultdict
 from contextlib import suppress
+from pathlib import Path
 from types import SimpleNamespace
 from typing import Literal, TypedDict, cast
 
@@ -236,9 +236,16 @@ def generate_zig_switch_arms(patch_sets: list[PatchSet]) -> str:
 
 
 if __name__ == "__main__":
-    source = sys.stdin.read()
+    project_root = Path(__file__).resolve().parents[2]
+
+    patcher_path = project_root / "vendor" / "nerd-fonts" / "font-patcher.py"
+    source = patcher_path.read_text(encoding="utf-8")
     patch_set = extract_patch_set_values(source)
-    print("""//! This is a generated file, produced by nerd_font_codegen.py
+
+    out_path = project_root / "src" / "font" / "nerd_font_attributes.zig"
+
+    with out_path.open("w", encoding="utf-8") as f:
+        f.write("""//! This is a generated file, produced by nerd_font_codegen.py
 //! DO NOT EDIT BY HAND!
 //!
 //! This file provides info extracted from the nerd fonts patcher script,
@@ -248,6 +255,7 @@ const Constraint = @import("face.zig").RenderOptions.Constraint;
 
 /// Get the a constraints for the provided codepoint.
 pub fn getConstraint(cp: u21) Constraint {
-    return switch (cp) {""")
-    print(generate_zig_switch_arms(patch_set))
-    print("        else => .none,\n    };\n}")
+    return switch (cp) {
+""")
+        f.write(generate_zig_switch_arms(patch_set))
+        f.write("\n        else => .none,\n    };\n}\n")