DOC improve DEV docs nav & text tweaks

server/sonar-docs/src/pages/extend/developing-plugin.md

@@ -1,5 +1,5 @@
 ---
-title: Developing a plugin
+title: Plugin basics
 url: /extend/developing-plugin/
 ---
 

server/sonar-docs/src/pages/extend/extend-web-app.md

@@ -1,5 +1,5 @@
 ---
-title: Extending the Web App
+title: Adding pages to the webapp
 url: /extend/extend-web-app/
 ---
 SonarQube provides the ability to add a new JavaScript page. A page (or page extension) is a JavaScript application that runs in the SonarQube environment. You can find the example of page extensions in the SonarQube or [sonar-custom-plugin-example](https://github.com/SonarSource/sonar-custom-plugin-example/tree/6.x/) repositories on GitHub. 

server/sonar-docs/src/pages/extend/i18n.md

@@ -5,7 +5,7 @@ url: /extend/i18n/
 
 This page gives guidelines to I18n for:
 
-* Plugin developers who would like to apply the i18n mechanism in their own plugin, so that this plugin can be available in several languages.
+* Plugin developers who would like to apply the i18n mechanism in their own plugins, so that these plugins can be available in several languages.
 * People who would like to help the community by making the platform available in a new language.
 
 ## Principles

server/sonar-docs/src/pages/extend/new-langauges.md

@@ -9,7 +9,7 @@ The steps to cover a new programming language are:
 1. Write the grammar. This is the hardest part.
 1. Write a parser (a parser simply parses an input based on your grammar to yield a parse tree).
 1. Test your grammar, to ensure it is able to parse real-life language files.
-1. Write a few parse tree visitors. Some visitors will compute metrics, while others will enforce [coding rules](/extend/adding-coding-rules/). A dozen or so visitors is sufficient for an initial release.
+1. Write a few parse tree visitors. Some visitors will compute metrics such as [executable lines](/extend/executable-lines/), while others will enforce [coding rules](/extend/adding-coding-rules/). A dozen or so visitors is sufficient for an initial release.
 1. Write a scanner Sensor, in a SonarQube plugin, to launch the visitors. 
 1. Compute
    1. issues

server/sonar-docs/static/SonarQubeNavigationTree.json

@@ -89,11 +89,16 @@
     "children": [
       "/extend/web-api/",
       "/extend/adding-coding-rules/",
-      "/extend/developing-plugin/",
-      "/extend/new-languages/",
-      "/extend/executable-lines/",
-      "/extend/adding-scm/",
-      "/extend/extend-web-app/",
+      {
+        "title": "Developing a plugin",
+        "children": [
+          "/extend/developing-plugin/",
+          "/extend/new-languages/",
+          "/extend/executable-lines/",
+          "/extend/extend-web-app/",
+          "/extend/adding-scm/"
+        ]
+      },
       "/extend/i18n/",
       "/extend/deploying-to-marketplace/",
       "/extend/contributing/"

server/sonar-docs/static/StaticNavigationTree.json

@@ -105,11 +105,16 @@
     "children": [
       "/extend/web-api/",
       "/extend/adding-coding-rules/",
-      "/extend/developing-plugin/",
-      "/extend/new-languages/",
-      "/extend/executable-lines/",
-      "/extend/adding-scm/",
-      "/extend/extend-web-app/",
+      {
+        "title": "Developing a plugin",
+        "children": [
+          "/extend/developing-plugin/",
+          "/extend/new-languages/",
+          "/extend/executable-lines/",
+          "/extend/extend-web-app/",
+          "/extend/adding-scm/"
+        ]
+      },
       "/extend/i18n/",
       "/extend/deploying-to-marketplace/",
       "/extend/contributing/"