Misc doc changes

List of changes:
- Fix typos
- Use common source url

README.md

@@ -7,7 +7,7 @@
 
 Elixir [Prometheus.io](https://prometheus.io) client based on [Prometheus.erl](https://github.com/deadtrickster/prometheus.erl).
 
-Starting from v3.0.0 works with Elixir >=1.6 and Erlang >=20. For older verions, please use older tags.
+Starting from v3.0.0 works with Elixir >=1.6 and Erlang >=20. For older versions, please use older tags.
 
 ![@skosch dashboard](https://aldusleaf.org/assets/images/2016/09/grafana.jpg)
 
@@ -63,7 +63,7 @@ Please read how to [measure durations correctly with prometheus.ex](https://hexd
  - [Extatus - App to report metrics to Prometheus from Elixir GenServers](https://github.com/gmtprime/extatus)
  - [Plugs Instrumenter/Exporter](https://github.com/deadtrickster/prometheus-plugs)
  - [Fuse plugin](https://github.com/jlouis/fuse#fuse_stats_prometheus)
- - [OS process info Collector](https://hex.pm/packages/prometheus_process_collector) (linux-only)
+ - [OS process info Collector](https://hex.pm/packages/prometheus_process_collector) (Linux-only)
  - [Phoenix instrumenter](https://github.com/deadtrickster/prometheus-phoenix)
  - [RabbitMQ Exporter](https://github.com/deadtrickster/prometheus_rabbitmq_exporter)
 

lib/prometheus.ex

@@ -38,7 +38,7 @@ defmodule Prometheus do
    - [Elixir plugs Instrumenters and Exporter](https://hex.pm/packages/prometheus_plugs);
    - [Fuse plugin](https://github.com/jlouis/fuse#fuse_stats_prometheus)
    - [OS process info Collector](https://hex.pm/packages/prometheus_process_collector)
-   (linux-only);
+   (Linux-only);
    - [Phoenix Instrumenter](https://hex.pm/packages/prometheus_phoenix);
    - [RabbitMQ Exporter](https://github.com/deadtrickster/prometheus_rabbitmq_exporter).
 

lib/prometheus/metric.ex

@@ -10,7 +10,7 @@ defmodule Prometheus.Metric do
   `@<type>` attributes. Metrics will be declared in
   the `@on_load` callback. If the module already
   has `@on_load` callback, metrics will be declared
-  iff the callback returns `:ok`.
+  if the callback returns `:ok`.
 
   Example:
 

lib/prometheus/metric/gauge.ex

@@ -10,7 +10,7 @@ defmodule Prometheus.Metric.Gauge do
   running processes.
 
   Example use cases for Gauges:
-    - Inprogress requests;
+    - In progress requests;
     - Number of items in a queue;
     - Free memory;
     - Total memory;
@@ -116,7 +116,7 @@ defmodule Prometheus.Metric.Gauge do
   delegate_metric dec(spec, value \\ 1)
 
   @doc """
-  Sets the gauge identified by `spec` to the current unixtime.
+  Sets the gauge identified by `spec` to the current unix time.
 
   Raises `Prometheus.UnknownMetricError` exception if a gauge
   for `spec` can't be found.<br>

lib/prometheus/metric/histogram.ex

@@ -1,7 +1,7 @@
 defmodule Prometheus.Metric.Histogram do
   @moduledoc """
   A Histogram tracks the size and number of events in buckets.
-  You can use Histograms for aggregatable calculation of quantiles.
+  You can use Histograms for aggregating calculation of quantiles.
 
   Example use cases for Histograms:
     - Response latency;

mix.exs

@@ -1,6 +1,7 @@
 defmodule PrometheusEx.Mixfile do
   use Mix.Project
 
+  @source_url "https://github.com/deadtrickster/prometheus.ex"
   @version "3.0.5"
 
   def project do
@@ -19,7 +20,7 @@ defmodule PrometheusEx.Mixfile do
       docs: [
         main: Prometheus,
         source_ref: "v#{@version}",
-        source_url: "https://github.com/deadtrickster/prometheus.ex",
+        source_url: @source_url,
         extras: [
           "pages/Mnesia Collector.md",
           "pages/VM Memory Collector.md",
@@ -46,7 +47,7 @@ defmodule PrometheusEx.Mixfile do
       maintainers: ["Ilya Khaprov"],
       licenses: ["MIT"],
       links: %{
-        "GitHub" => "https://github.com/deadtrickster/prometheus.ex",
+        "GitHub" => @source_url,
         "Prometheus.erl" => "https://hex.pm/packages/prometheus",
         "Inets HTTPD Exporter" => "https://hex.pm/packages/prometheus_httpd",
         "Ecto Instrumenter" => "https://hex.pm/packages/prometheus_ecto",