docs: Fix a typo in README (#8036)

Fix a typo in README.

# Which issue does this PR close?

- Closes #NNN.

# Rationale for this change

Fix typo

# What changes are included in this PR?

Fix typo

# Are these changes tested?

Nope.

# Are there any user-facing changes?

Nope.

Signed-off-by: Cheng-Yang Chou <[email protected]>

Author: EricccTaiwan

README.md

@@ -108,7 +108,7 @@ The deprecated version is the next version which will be released (please
 consult the list above). To mark the API as deprecated, use the
 `#[deprecated(since = "...", note = "...")]` attribute.
 
-Foe example
+For example
 
 ```rust
 #[deprecated(since = "51.0.0", note = "Use `date_part` instead")]