General documentation improvements (#8302)

lib/elixir/lib/kernel.ex

@@ -1920,8 +1920,8 @@ defmodule Kernel do
   end
 
   @doc """
-  Matches the term on the left against the regular expression or string on the
-  right.
+  Matches the term on the `left` against the regular expression or string on the
+  `right`.
 
   Returns `true` if `left` matches `right` (if it's a regular expression)
   or contains `right` (if it's a string).

lib/elixir/lib/process.ex

@@ -103,7 +103,7 @@ defmodule Process do
   Stores the given `key`-`value` pair in the process dictionary.
 
   The return value of this function is the value that was previously stored
-  under `key`, or `nil` in case no value was stored under `key`.
+  under `key`, or `nil` in case no value was stored under it.
 
   ## Examples
 

lib/ex_unit/test/ex_unit_test.exs

@@ -136,7 +136,7 @@ defmodule ExUnitTest do
     assert config[:max_cases] == 1
   end
 
-  test "filters to the given test ids when an `only_test_ids` option is provided" do
+  test "filters to the given test IDs when the `only_test_ids` option is provided" do
     defmodule TestIdTestModule do
       use ExUnit.Case