Add support for adjusting thickness of underline cursor

Signed-off-by: Aaron Ruan <i@ar212.com>

src/font/sprite.zig

@@ -32,6 +32,7 @@ pub const Sprite = enum(u32) {
     cursor_rect,
     cursor_hollow_rect,
     cursor_bar,
+    cursor_underline,
 
     // Note: we don't currently put the box drawing glyphs in here because
     // there are a LOT and I'm lazy. What I want to do is spend more time

src/font/sprite/Face.zig

@@ -174,6 +174,7 @@ const Kind = enum {
                 .cursor_rect,
                 .cursor_hollow_rect,
                 .cursor_bar,
+                .cursor_underline,
                 => .cursor,
             },
 

src/font/sprite/cursor.zig

@@ -43,6 +43,12 @@ pub fn renderGlyph(
             .width = thickness,
             .height = height,
         }, .on),
+        Sprite.cursor_underline => canvas.rect(.{
+            .x = 0,
+            .y = height -| thickness,
+            .width = width,
+            .height = thickness,
+        }, .on),
         else => unreachable,
     }
 

src/renderer/generic.zig

@@ -2868,7 +2868,7 @@ pub fn Renderer(comptime GraphicsAPI: type) type {
                         .block => .cursor_rect,
                         .block_hollow => .cursor_hollow_rect,
                         .bar => .cursor_bar,
-                        .underline => .underline,
+                        .underline => .cursor_underline,
                         .lock => unreachable,
                     };