fix(filter): Remove 'parse' on no_std

Author: epage

crates/env_filter/src/filter.rs

@@ -98,6 +98,7 @@ impl Builder {
     /// See the [Enabling Logging] section for more details.
     ///
     /// [Enabling Logging]: ../index.html#enabling-logging
+    #[cfg(feature = "std")]
     pub fn parse(&mut self, filters: &str) -> &mut Self {
         #![allow(clippy::print_stderr)] // compatibility
 
@@ -108,7 +109,6 @@ impl Builder {
         } = parse_spec(filters);
 
         for error in errors {
-            #[cfg(feature = "std")]
             eprintln!("warning: {error}, ignoring it");
         }