Fix typos in developer (#5785)

* Fix typo to make reading better in developer/text-conventions.md
Signed-off-by: NydFu <ader.ydfu@gmail.com>

docs/developer/text-conventions.md

@@ -6,13 +6,13 @@ Kubernetes Dashboard is a web-based user interface for Kubernetes clusters. It c
 
 As you noticed there are a lot of different kinds of text messages in each view:
 
-* Titles,
-* Headers,
-* Labels,
-* Values,
-* Tooltips,
-* Action button,
-* Menu and navigation entries,
+* Titles.
+* Headers.
+* Labels.
+* Values.
+* Tooltips.
+* Action button.
+* Menu and navigation entries.
 * All kinds of messages including warnings, errors and help information.
 
 For each one of them a developer has to make the following decisions:
@@ -37,18 +37,18 @@ Certain types of text resources should have punctuation. Periods should be used
 
 Periods should be avoided for:
 
-* Headers,
-* Titles,
-* Labels,
-* Values,
-* Tooltips,
+* Headers.
+* Titles.
+* Labels.
+* Values.
+* Tooltips.
 * Menu and navigation entries.
 
 ### Capitalization
 
 In general, all kinds of messages should have their first word capitalized. Exceptions are:
 
-* Names which appear in the middle of a message,
+* Names which appear in the middle of a message.
 * Values and table contents.
 
 Moreover, Kubernetes-specific names should be capitalized everywhere. This includes:
@@ -56,7 +56,5 @@ Moreover, Kubernetes-specific names should be capitalized everywhere. This inclu
 * Application names - Kubernetes, Kubernetes Dashboard etc.
 * Resource names - Pod, Service, Endpoint, Node etc.
 
-
-
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 _Copyright 2019 [The Kubernetes Dashboard Authors](https://github.com/kubernetes/dashboard/graphs/contributors)_