fix(man): simplify groff invocation to match working command

Use `groff -Tutf8 -P-cbou -man` which produces clean plain-text output
without ANSI escapes or backspace overstrikes.

https://claude.ai/code/session_01CrXuWDMVQsiUBoy6ceACsF

Author: claude

cli/man_page.rs

@@ -62,10 +62,7 @@ fn man_path(page_num: u8) -> String {
 fn render_man_output(page_num: u8) -> Result<String, String> {
     let roff_file = roff_path(page_num);
     let output = Command::new("groff")
-        .args([
-            "-man", "-T", "utf8", "-K", "utf8", "-P", "-c", "-P", "-b", "-P", "-u",
-        ])
-        .env("GROFF_NO_SGR", "1")
+        .args(["-man", "-Tutf8", "-P-cbou"])
         .arg(format!("-rLL={LINE_LENGTH}n"))
         .arg(format!("./{roff_file}"))
         .output()