contributing.md: various tweaks (#1100)

- adjust whitespace & line breaks to make the markdown source more readable and consistent
- remove "we"/"our", to avoid reinforcing the "us vs. them" paradigm
- clarify a couple passages
- remove obsolete license agreement notice, now covered by the CLA
- remove redundant (and oddly specific) plea for contributions and the end of the document,
  since there's already one at the beginning
- remove a redundant example of commit message format

CONTRIBUTING.md

@@ -11,12 +11,16 @@ To get started, sign the [Contributor License Agreement](https://cla-assistant.i
 The basic format of a `tldr` page is a set of concrete usage examples.
 Here are a few guidelines to get started:
 
-1. Focus on the 5 or 6 most common usages. It's OK if the page doesn't cover everything; that's what `man` is for.
-2. When in doubt, keep new command-line users in mind. Err on the side of clarity rather than terseness.
+1. Focus on the 5 or 6 most common usages.
+   It's OK if the page doesn't cover everything; that's what `man` is for.
+2. When in doubt, keep new command-line users in mind.
+   Err on the side of clarity rather than terseness.
 3. Try to incorporate the spelled-out version of single-letter options in the example's description.
    The goal is to allow people to *understand* the syntax of the commands, not just *memorize* it.
-4. Introduce options gradually, starting with the simplest commands and using more complex examples progressively.
-5. Use short but descriptive values for the tokens, ex. `{{source_file}}` or `{{wallet.txt}}`.
+4. Introduce options gradually, starting with the simplest command invocations,
+   and using more complex examples progressively.
+5. Use short but descriptive values for the tokens,
+   ex. `{{source_file}}` or `{{wallet.txt}}`.
 6. Focus on details specific to the command, and avoid explaining general UNIX concepts that could apply to any command
    (ex: relative/absolute paths, glob patterns/wildcards, special character escaping...).
 
@@ -41,7 +45,7 @@ The format of each page should match the following:
 `command -opt1 -opt2`
 ```
 
-We actually have a linter/formatter that enforces our format.
+There actually is a linter/formatter that enforces the format above.
 It is run automatically on every pull request,
 but you may install it to test your contributions locally before submitting them:
 
@@ -54,31 +58,38 @@ For other ways to use `tldrl`, such as linting an entire directory, check out (w
 [`tldr tldrl`](https://github.com/tldr-pages/tldr/blob/master/pages/common/tldrl.md)
 
 ### Token syntax
-User-provided values should use the `{{token}}` syntax
-in order to allow clients to highlight them.
-Use [`snake_case`](https://en.wikipedia.org/wiki/Snake_case)
-for multi-word tokens.
+
+User-provided values should use the `{{token}}` syntax in order to allow `tldr` clients to highlight them.
+Use [`snake_case`](https://en.wikipedia.org/wiki/Snake_case) for multi-word tokens.
 
 Keep the following guidelines in mind when choosing token names:
 
-- If the example is clearer with an actual value rather than a generic placeholder, use the actual value. For example, use `iostat {{2}}` rather than `iostat {{interval_in_secs}}`.
+- If the example is clearer with an actual value rather than a generic placeholder,
+  use the actual value. For example, use `iostat {{2}}` rather than `iostat {{interval_in_secs}}`.
 
-- For any reference to paths to files or folders, use `{{path/to/<placeholder>}}`. For example, `ln -s {{path/to/file}} {{path/to/symlink}}`. In case of a possible reference both to a file or a folder, use `{{path/to/file_or_folder}}`
+- For any reference to paths to files or folders, use `{{path/to/<placeholder>}}`.
+  For example, `ln -s {{path/to/file}} {{path/to/symlink}}`.
+  In case of a possible reference both to a file or a folder, use `{{path/to/file_or_folder}}`
 
-- If a command expects the file to have a particular extension, use it. For example, `unrar x {{compressed.rar}}`. In case needs a generic extension, use `{{.ext}}`, but **only** if it helps to clarify the command. For example, here:
+- If a command expects the file to have a particular extension, use it.
+  For example, `unrar x {{compressed.rar}}`.
+  In case needs a generic extension, use `{{.ext}}`, but **only** if it helps to clarify the command.
+  For example, here:
 
   ```
   Open all the files of a given extension in the current directory with the associated application:
   open {{*.ext}}
   ```
 
-  ... using `{{.ext}}` helps to clarify the command. But in a command like `wc -l {{file}}`, using `{{file}}` is sufficiently clear.
+  ... using `{{.ext}}` helps to clarify the command.
+  But in a command like `wc -l {{file}}`, using `{{file}}` is sufficiently clear.
 
-- Lastly, follow the `{{path/to/<placeholder>}}` convention when there is a path-related command. Not when the file location is implicit. But of course, use proper judgement, keeping simplicity and user friendliness as the top priority.
+- Lastly, follow the `{{path/to/<placeholder>}}` convention when there is a path-related command,
+  except when the file location is implicit.
+  But of course, use proper judgement, keeping simplicity and user friendliness as the top priority.
 
-In short, make it as intuitive as possible
-for the user to figure out how to use the command
-and fill it in with values.
+In short, choose tokens that make it as intuitive as possible
+for the user to figure out how to use the command and fill it in with values.
 
 ## Submitting a pull request
 
@@ -125,17 +136,10 @@ Examples:
   - `ls: add page`
   - `cat: fix typo`
   - `git-push: add --force example`
-  - `uname: fix -a example`
 
 ## Licensing
 
 `tldr` is licensed under the [MIT license](https://github.com/tldr-pages/tldr/blob/master/LICENSE.md).
 
-**IMPORTANT**: By submitting a patch, you agree to license your work
-under the same license as that used by the project.
-
-You're free to modify or redistribute the content.
-That being said, but why not contribute over here? :)
-Say if you wanted to have `tldr` pages in `groff` format,
-why not have a client that uses [pandoc](http://johnmacfarlane.net/pandoc/)
-and periodically updates straight from this repo?
+Any contributions to this project are governed by the
+[Contributor License Agreement](https://cla-assistant.io/tldr-pages/tldr).