Update docs: Correct 'argument' to 'parameter', fix whitespace & EOF. (#5454)

In some places “argument type” was used and this has been corrected into
“parameter type”.
Some trailing whitespaces where removed.
One file didn’t end in a newline and this has been fixed.

Author: ath

CONTRIBUTING.md

@@ -53,7 +53,7 @@ More info:
 
 ## Updating code samples
 
-If your PR changes Dart code within a page, 
+If your PR changes Dart code within a page,
 you'll probably need to change the code in two places:
 
 1. In a `.md` file for the page.

diagrams/README.md

@@ -2,12 +2,12 @@
 
 This directory contains sources for generating images used across the website.
 
-These come in various forms, such as 
-`.graffle` used by the [OmniGraffle][] tool 
+These come in various forms, such as
+`.graffle` used by the [OmniGraffle][] tool
 as well as PNGs and SVGs generated with [diagrams.net][].
 
-Do **NOT** optimize any images or vectors that are in this directory. 
+Do **NOT** optimize any images or vectors that are in this directory.
 They contain metadata used by editors to enable editing the image.
 
 [OmniGraffle]: https://www.omnigroup.com/omnigraffle/
-[diagrams.net]: https://www.diagrams.net/
+[diagrams.net]: https://www.diagrams.net/

src/language/extend.md

@@ -62,10 +62,10 @@ the method (or methods) that it overrides in several ways:
 
 * The return type must be the same type as (or a subtype of)
   the overridden method's return type.
-* Argument types must be the same type as (or a supertype of)
-  the overridden method's argument types.
+* Parameter types must be the same type as (or a supertype of)
+  the overridden method's parameter types.
   In the preceding example, the `contrast` setter of `SmartTelevision`
-  changes the argument type from `int` to a supertype, `num`.
+  changes the parameter type from `int` to a supertype, `num`.
 * If the overridden method accepts _n_ positional parameters,
   then the overriding method must also accept _n_ positional parameters.
 * A [generic method][] can't override a non-generic one,
@@ -77,10 +77,10 @@ This violates the normal rules, and
 it's similar to a downcast in that it can cause a type error at runtime.
 Still, narrowing the type is possible
 if the code can guarantee that a type error won't occur.
-In this case, you can use the 
+In this case, you can use the
 [`covariant` keyword](/guides/language/sound-problems#the-covariant-keyword)
 in a parameter declaration.
-For details, see the 
+For details, see the
 [Dart language specification][].
 
 {{site.alert.warning}}

src/tools/pub/cmd/pub-get.md

@@ -26,7 +26,7 @@ doesn't already contain the dependencies, `dart pub get`
 updates the cache,
 downloading dependencies if necessary.
 To map packages back to the system cache,
-this command creates a `package_config.json` file 
+this command creates a `package_config.json` file
 in the `.dart_tool/` directory.
 
 Once the dependencies are acquired, they may be referenced in Dart code.
@@ -63,7 +63,7 @@ in the `.dart_tool/` directory that maps from package names to location URIs.
 {{site.alert.note}}
   Don't check the generated `.dart_tool/` directory into your repo;
   add it to your repo's `.gitignore` file.
-  For more information, 
+  For more information,
   see [What not to commit](/guides/libraries/private-files).
 {{site.alert.end}}
 

src/tools/pub/cmd/pub-global.md

@@ -74,7 +74,7 @@ $ dart pub global activate -sgit https://github.com/dart-lang/async_await.git
 ```
 
 Pub expects to find the package in the root of the Git repository.
-To specify a different location, 
+To specify a different location,
 use the `--git-path` option with
 a path relative to the repository root:
 
@@ -229,8 +229,8 @@ For options that apply to all pub commands, see
 
 ### `[version-constraint]`
 
-Use `dart pub global activate <package> [version-constraint]` 
-to specify a specific version of the package. 
+Use `dart pub global activate <package> [version-constraint]`
+to specify a specific version of the package.
 For example, the following command pulls
 the 0.6.0 version of the `markdown` package:
 
@@ -259,7 +259,7 @@ to add the specified executable to your PATH.
 You can pass more than one of these flags.
 
 For example, the following command adds `bar` and `baz`,
-(but not any other executables that `foo` might define) 
+(but not any other executables that `foo` might define)
 to your PATH.
 
 ```terminal

src/tools/pub/cmd/pub-outdated.md

@@ -81,7 +81,7 @@ you just need to run `dart pub upgrade`:
 
 ```terminal
 $ dart pub upgrade
-Resolving dependencies... 
+Resolving dependencies...
 > args 1.6.0 (was 1.4.4)
   ...
 Changed 1 dependency!
@@ -111,15 +111,15 @@ due to constraints determined by other dependencies:
 $ dart pub upgrade
 ...
 $ dart pub outdated
-Package Name  Current  Upgradable  Resolvable  Latest 
+Package Name  Current  Upgradable  Resolvable  Latest
 
 direct dependencies:
-path          1.6.2    1.6.2       1.6.2       1.7.0   
+path          1.6.2    1.6.2       1.6.2       1.7.0
 
 dev_dependencies: all up-to-date
 
 transitive dependencies:
-meta          1.1.6    1.1.6       1.1.6       1.1.8   
+meta          1.1.6    1.1.6       1.1.6       1.1.8
 
 transitive dev_dependencies: all up-to-date
 

src/tools/pub/cmd/pub-remove.md

@@ -30,7 +30,7 @@ For options that apply to all pub commands, see
 
 ### `-n, --dry-run`
 
-Reports which dependencies would change, 
+Reports which dependencies would change,
 but doesn't change any.
 
 ### `--[no-]precompile`