just do everything i guess

lib/manpage.ml

@@ -655,6 +655,15 @@ let extract_name_description contents =
  * we hit something that looks like an argument (starts with [, <, -, etc.). *)
 
 let extract_synopsis_command_lines lines =
+  (* replace italic text (\fI...\fR) with angle-bracketed placeholders
+   * before classification strips the font info. italic in groff indicates
+   * a parameter/placeholder (e.g. \fIoperation\fR), not a command word.
+   * the angle brackets cause extract_cmd to stop at these tokens since
+   * '<' is in its stop set. without this, "nix-env \fIoperation\fR"
+   * would be parsed as command "nix-env operation" instead of "nix-env". *)
+  let lines = List.map (fun line ->
+    Str.global_replace (Str.regexp {|\\fI\([^\\]*\)\\f[RP]|}) {|<\1>|} line
+  ) lines in
   let classified = List.map classify_line lines in
   let is_synopsis name =
     String.uppercase_ascii (String.trim name) = "SYNOPSIS"