font: fix nerd font patcher ypadding twice what it should be

The nerd font patcher uses `ypadding` as a single subtraction from the
cell height, which means that half of it should go to the top padding
and the other half to the bottom, this was making the heavy brackets way
too small lol (0.4 of the cell height instead of 0.7)

src/font/nerd_font_attributes.zig

@@ -40,8 +40,8 @@ pub fn getConstraint(cp: u21) Constraint {
             .max_constraint_width = 1,
             .align_horizontal = .center,
             .align_vertical = .center,
-            .pad_top = 0.3,
-            .pad_bottom = 0.3,
+            .pad_top = 0.15,
+            .pad_bottom = 0.15,
         },
         0xe0b0,
         => .{

src/font/nerd_font_codegen.py

@@ -213,8 +213,8 @@ def emit_zig_entry_multikey(codepoints: list[int], attr: PatchSetAttributeEntry)
         s += f"            .pad_top = {v_pad},\n"
         s += f"            .pad_bottom = {v_pad},\n"
     elif y_padding:
-        s += f"            .pad_top = {y_padding},\n"
-        s += f"            .pad_bottom = {y_padding},\n"
+        s += f"            .pad_top = {y_padding / 2},\n"
+        s += f"            .pad_bottom = {y_padding / 2},\n"
 
     if xy_ratio > 0:
         s += f"            .max_xy_ratio = {xy_ratio},\n"