Proofreading PolyGerrit plugin dev docs

Change-Id: I9c971b607c2a5cdbcbb44b7837534743e6662ed1

Documentation/pg-plugin-dev.txt

@@ -21,7 +21,7 @@ spec.
   located in `gerrit-site/plugins` folder, where `pluginname` is an alphanumeric
   plugin name.
 
-Note: Code examples target modern brosers (Chrome, Firefox, Safari, Edge)
+Note: Code examples target modern browsers (Chrome, Firefox, Safari, Edge).
 
 Here's a recommended starter `myplugin.html`:
 
@@ -132,17 +132,17 @@ Note: TODO: Insert link to the full styling API.
 [[high-level-api-concepts]]
 == High-level DOM API concepts
 
-High leve API is based on low-level DOM API and is essentially a standartized
+High level API is based on low-level DOM API and is essentially a standardized
 way for doing common tasks. It's less flexible, but will be a bit more stable.
 
-Common way to access high-leve API is through `plugin` instance passed into
+The common way to access high-level API is through `plugin` instance passed
-setup callback parameter of `Gerrit.install()`, also sometimes referred as
+into setup callback parameter of `Gerrit.install()`, also sometimes referred to
-`self`.
+as `self`.
 
 [[low-level-api]]
 == Low-level DOM API
 
-Low-level DOM API methods are the base of all UI customization.
+The low-level DOM API methods are the base of all UI customization.
 
 === attributeHelper
 `plugin.attributeHelper(element)`

Documentation/pg-plugin-endpoints.txt

@@ -1,6 +1,6 @@
 = Gerrit Code Review - PolyGerrit Plugin Styling
 
-Plugin should be html-based and imported following PolyGerrit's
+Plugins should be html-based and imported following PolyGerrit's
 link:pg-plugin-dev.html#loading[dev guide].
 
 Sample code for testing endpoints:
@@ -19,8 +19,8 @@ Gerrit.install(plugin => {
 ```
 
 == Default parameters
-All endpoints receive the following params, set as attributes to custom components
+All endpoints receive the following parameters, set as attributes to custom
-that are instantiated at the endpoint:
+components that are instantiated at the endpoint:
 
 * `plugin`
 +
@@ -33,12 +33,12 @@ components.
 
 == Plugin endpoints
 
-Following endpoints are available to plugins
+The following endpoints are available to plugins.
 
 === change-view-integration
-Extension point is located between `Files` and `Messages` section on the change
+This extension point is located between `Files` and `Messages` section on the
-view page, and it may take full page's width. Primary purpose is to enable
+change view page, and it may take full page's width. Primary purpose is to
-plugins to display custom CI related information (build status, etc).
+enable plugins to display custom CI-related information (build status, etc).
 
 * `change`
 +
@@ -51,10 +51,10 @@ current revision displayed, an instance of
 link:rest-api-changes.html#revision-info[RevisionInfo]
 
 === change-metadata-item
-Extension point is located on the bottom of the change view left panel, under
+The change-metadata-item extension point is located on the bottom of the change
-`Label Status` and `Links` sections. It's width is equal to the left panel's and
+view left panel, under the `Label Status` and `Links` sections. Its width is
-primary purpose is to enable plugins to add sections of metadata to the left
+equal to the left panel's, and its primary purpose is to allow plugins to add
-panel.
+sections of metadata to the left panel.
 
 In addition to default parameters, the following are available:
 

Documentation/pg-plugin-styling.txt

@@ -10,16 +10,16 @@ PolyGerrit UI implements number of styling endpoints, which apply CSS mixins
 link:https://tabatkins.github.io/specs/css-apply-rule/[using @apply] to its
 direct contents.
 
-NOTE: Only items (ie CSS properties and mixin targets) documented here are
+NOTE: Only items (i.e. CSS properties and mixin targets) documented here are
 guaranteed to work in the long term, since they are covered by integration
 tests. + When there is a need to add new property or endpoint, please
 link:https://bugs.chromium.org/p/gerrit/issues/entry?template=PolyGerrit%20Issue[file
-a bug] stating your usecase to track and maintain for future releases.
+a bug] stating your use case to track and maintain for future releases.
 
-Plugin should be html-based and imported following PolyGerrit's
+Plugins should be html-based and imported following PolyGerrit's
 link:pg-plugin-dev.html#loading[dev guide].
 
-Plugin should provide Style Module, for example:
+Plugins should provide Style Module, for example:
 
 ``` html
   <dom-module id="some-style">
@@ -33,7 +33,7 @@ Plugin should provide Style Module, for example:
   </dom-module>
 ```
 
-Plugin should register style module with a styling endpoint using
+Plugins should register style module with a styling endpoint using
 `Plugin.prototype.registerStyleModule(endpointName, styleModuleName)`, for
 example:
 
@@ -45,7 +45,7 @@ example:
 
 == Available styling endpoints
 === change-metadata
-Following custom css mixins are recognized:
+Following custom CSS mixins are recognized:
 
 * `--change-metadata-assignee`
 +