Also migrate tests from failure to anyhow

Author: swallez

api_generator/src/generator/output.rs

@@ -185,7 +185,7 @@ mod test {
     use std::fs;
 
     #[test]
-    pub fn nominal_merge() -> anyhow::Result<(), failure::Error> {
+    pub fn nominal_merge() -> anyhow::Result<()> {
         let dir = tempfile::tempdir()?;
         let dir_path = dir.path();
         let file_name = "test_merge.rs";
@@ -249,7 +249,7 @@ Contents of section bar
     }
 
     #[test]
-    fn unbalanced_sections() -> Result<(), failure::Error> {
+    fn unbalanced_sections() -> anyhow::Result<()> {
         merge_should_fail(
             r#"
 // GENERATED-BEGIN:foo
@@ -280,7 +280,7 @@ Contents of section bar
         Ok(())
     }
 
-    fn merge_should_fail(input: &str) -> Result<(), failure::Error> {
+    fn merge_should_fail(input: &str) -> anyhow::Result<()> {
         let dir = tempfile::tempdir()?;
         let dir_path = dir.path();
         let file_name = "test_merge.rs";