Fixing addressing

- Fix double resolve bug in address handler
- Fix multiple major issues with next_closing and prev_opening functions.
- add `=` ed command.
- Other minor fixes.

src/internal/commands/commands.cc

@@ -101,6 +101,21 @@ void Command::register_posix(BEd &ctx) {
       }
     }
   );
+  ctx.commands.insert(
+    "=",
+    Command{
+      .address_mode = Command::AddressMode::Single,
+      .suffix = Command::SuffixKind::Suffix,
+      .desc = "Print line number",
+      .accept_zero = false,
+      .handle = [](BEd &ctx, std::span<const uint64_t> addresses, std::string_view) {
+        if (!addresses.size())
+          std::cout << ctx.active->vase.lines() << std::endl;
+        else
+          std::cout << addresses[0] << std::endl;
+      }
+    }
+  );
   ctx.commands.insert(
     "debug",
     Command{