globset: expand docs and impl Default for GlobSet

Closes #1882, Closes #1883

crates/globset/src/glob.rs

@@ -616,6 +616,8 @@ impl<'a> GlobBuilder<'a> {
     }
 
     /// Toggle whether a literal `/` is required to match a path separator.
+    ///
+    /// By default this is false: `*` and `?` will match `/`.
     pub fn literal_separator(&mut self, yes: bool) -> &mut GlobBuilder<'a> {
         self.opts.literal_separator = yes;
         self

crates/globset/src/lib.rs

@@ -456,6 +456,13 @@ impl GlobSet {
     }
 }
 
+impl Default for GlobSet {
+    /// Create a default empty GlobSet.
+    fn default() -> Self {
+        GlobSet::empty()
+    }
+}
+
 /// GlobSetBuilder builds a group of patterns that can be used to
 /// simultaneously match a file path.
 #[derive(Clone, Debug)]
@@ -833,7 +840,7 @@ impl RequiredExtensionStrategyBuilder {
 
 #[cfg(test)]
 mod tests {
-    use super::GlobSetBuilder;
+    use super::{GlobSet, GlobSetBuilder};
     use glob::Glob;
 
     #[test]
@@ -863,4 +870,11 @@ mod tests {
         assert!(!set.is_match(""));
         assert!(!set.is_match("a"));
     }
+
+    #[test]
+    fn default_set_is_empty_works() {
+        let set: GlobSet = Default::default();
+        assert!(!set.is_match(""));
+        assert!(!set.is_match("a"));
+    }
 }