update readme and other texts

.github/ISSUE_TEMPLATE/bug_report.md

@@ -22,14 +22,14 @@ A clear and concise description of what you expected to happen.
 
 **Screenshots**
 If applicable, add screenshots to help explain your problem.
-If you add screenshots, please reduce the size or use thumbnails to keep the issue nicely readable.
+If you add screenshots, **reduce the size or use thumbnails** to keep the issue nicely readable.
 
 **App version**
-Which exact version of this fork is affected?
+Which _exact_ version of this fork is affected?
 
 **Smartphone (please complete the following information):**
  - Device: [e.g. Samsung Galaxy S9]
- - OS: [e.g. Android 10]
+ - OS: [e.g. Android 10] (add details if you are not using a version provided by the device manufacturer)
 
 **Additional context**
 Add any other context about the problem here.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -24,4 +24,4 @@ Please use this for requesting a single feasture, and open more issues for furth
 
 **Additional context**
 <!-- Add any other context or screenshots about the feature request here.
-If you add screenshots, please reduce the size or use thumbnails to keep the issue nicely readable. -->
+If you add screenshots, reduce the size or use thumbnails to keep the issue nicely readable. -->

.github/ISSUE_TEMPLATE/other.md

@@ -8,5 +8,5 @@ Please search open and closed issues to avoid duplicates.
 
 Note that this version of OpenBoard is focusing only on a few things. You can add a feature request or open other issues, but at the current stage it could take a long time until things are improved or even until you get a response.
 
-If you add screenshots, please reduce the size or use thumbnails to keep the issue nicely readable.
+If you add screenshots, reduce the size or use thumbnails to keep the issue nicely readable.
 -->