Fix markdown formatting for (blank) in docs (#3850)

I realize I'm rolling the dice by opening a PR without a pre-approved
issue, but I'll take that chance. Feel free to close if this isn't
desired; no hard feelings!

Currently, the docs for `cursor-style-blink` have two backticks side by
side in the docs, which end up rendering as actual backticks rather than
a code-formatted blank space:

<img width="721" alt="Screenshot 2024-12-28 at 11 19 02 PM"
src="https://github.com/user-attachments/assets/295369d6-624f-4efe-a7ea-495c9fd216bb"
/>

This change puts a space between the backticks so they render as a
code-formatted space.

Author: mitchellh

src/config/Config.zig

@@ -485,7 +485,7 @@ palette: Palette = .{},
 ///
 /// Valid values are:
 ///
-///   * `` (blank)
+///   * ` ` (blank)
 ///   * `true`
 ///   * `false`
 ///