fs: fix spelling mistakes in comment

Fix three spelling errors in the comment for an internal file structure
allocation function:
- happend  →  happened
- over     →  exceed (grammatical fix)
- int      →  in

Changes since v1:
- Fix comma after e.g.
- Fix incorrect use of "imbalance"

Signed-off-by: Qingshuang Fu <fuqingshuang@kylinos.cn>
Link: https://patch.msgid.link/20260527100025.960339-1-fffsqian@163.com
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

fs/file_table.c

@@ -231,13 +231,13 @@ static int init_file(struct file *f, int flags, const struct cred *cred)
 }
 
 /* Find an unused file structure and return a pointer to it.
- * Returns an error pointer if some error happend e.g. we over file
+ * Returns an error pointer if some error happened, e.g., we exceed the file
  * structures limit, run out of memory or operation is not permitted.
  *
  * Be very careful using this.  You are responsible for
  * getting write access to any mount that you might assign
  * to this filp, if it is opened for write.  If this is not
- * done, you will imbalance int the mount's writer count
+ * done, the mount's writer count will be wrong
  * and a warning at __fput() time.
  */
 struct file *alloc_empty_file(int flags, const struct cred *cred)