Fix:git checkout -- <file_name> is incorrect git-tips#177

Author: arnabnandy7

README.md

@@ -334,7 +334,7 @@ git tag -d <tag-name>
 git push origin :refs/tags/<tag-name>
 ```
 
-## Undo local changes with the last content in head
+## Undo local changes with the content in index(staging)
 ```sh
 git checkout -- <file_name>
 ```

tips.json

@@ -75,7 +75,7 @@
 		"title": "Delete remote tag",
 		"tip": "git push origin :refs/tags/<tag-name>"
 	}, {
-		"title": "Undo local changes with the last content in head",
+		"title": "Undo local changes with the content in index(staging)",
 		"tip": "git checkout -- <file_name>"
 	}, {
 		"title": "Revert: Undo a commit by creating a new commit",