doc: fix quote

remove the coma character by using ' character

Signed-off-by: Jingjing Wu <jingjing.wu@intel.com>

diff --git a/doc/guides/testpmd_app_ug/testpmd_funcs.rst b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
index 106b3cf..4d430ff 100644 (file)
--- a/doc/guides/testpmd_app_ug/testpmd_funcs.rst
+++ b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
@@ -1549,7 +1549,7 @@ Configure flexible payload selection.
 
 flow_director_flex_payload (port_id) (raw|l2|l3|l4) (config)
 
-For example, to select the first 16 bytes from the offset 4 (bytes) of packet’s payload as flexible payload.
+For example, to select the first 16 bytes from the offset 4 (bytes) of packet's payload as flexible payload.
 
 .. code-block:: console