Minor improvement of variable naming accuracy

build/syntax_mapping.rs

@@ -172,10 +172,10 @@ impl MappingDefModel {
         let list = self
             .mappings
             .into_iter()
-            .flat_map(|(target, matcher)| {
-                matcher
+            .flat_map(|(target, matchers)| {
+                matchers
                     .into_iter()
-                    .map(|rule| (rule, target.clone()))
+                    .map(|matcher| (matcher, target.clone()))
                     .collect::<Vec<_>>()
             })
             .collect();

src/syntax_mapping/builtins/README.md

@@ -51,7 +51,8 @@ handle things like [XDG](https://specifications.freedesktop.org/basedir-spec/lat
 All environment variables intended to be replaced at runtime must be enclosed in
 `${}`, for example `"/foo/*/${YOUR_ENV}-suffix/*.log"`. Note that this is the
 **only** admissible syntax; other variable substitution syntaxes are not
-supported and are thus treated as plain text.
+supported and will either cause a compile time error, or be treated as plain
+text.
 
 For example, if `foo-application` also supports per-user configuration files, we
 could write something like this: