Update to rt-format 0.3.0 and drop TryInto<usize> impl

Cargo.lock

@@ -291,9 +291,9 @@ checksum = "f497285884f3fcff424ffc933e56d7cbca511def0c9831a7f9b5f6153e3cc89b"
 
 [[package]]
 name = "rt-format"
-version = "0.2.1"
+version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "47343e4f2a81ef78a44ae1b1b8667ae11e5f89a6c1a3d788bd51b243e03387c4"
+checksum = "953eff237fc52cbb1a78d9ef62de48422a42c49c4db65b7e7e9d3aa500b1bdae"
 dependencies = [
  "lazy_static",
  "regex",

Cargo.toml

@@ -19,4 +19,4 @@ directories = "4.0"
 regex = "1.5.4"
 lazy_static = "1.4.0"
 rand = "0.8.4"
-rt-format = "0.2.0"
+rt-format = "0.3.0"

src/rtfmt.rs

@@ -66,13 +66,6 @@ impl<'a> FormatArgument for FmtArg<'a> {
     }
 }
 
-impl<'a> std::convert::TryInto<usize> for &FmtArg<'a> {
-    type Error = ();
-    fn try_into(self) -> Result<usize, Self::Error> {
-        Err(())
-    }
-}
-
 pub fn format(fmt: &str, arg: &str, clipped_str: &str) -> String {
     let args = &[FmtArg::Str(arg)];