[hotfix][doc] fix puncutation

Author: JingGe

docs/content.zh/docs/deployment/overview.md

@@ -172,7 +172,7 @@ covered by [FLINK-26606](https://issues.apache.org/jira/browse/FLINK-26606).
 
 Flink can execute applications in two modes:
 - Application Mode,
-- Session Mode,
+- Session Mode.
 
  The above modes differ in:
  - the cluster lifecycle and resource isolation guarantees

docs/content/docs/deployment/overview.md

@@ -173,7 +173,7 @@ covered by [FLINK-26606](https://issues.apache.org/jira/browse/FLINK-26606).
 
 Flink can execute applications in two modes:
 - Application Mode,
-- Session Mode,
+- Session Mode.
 
  The above modes differ in:
  - the cluster lifecycle and resource isolation guarantees