README: fix markdown formatting

- limit line length (does not affect rendering)
- add first-level header first
- converted google domain from hyperlinks into plain text
- add language specification for code fragments

Here is a command to run Markdown syntax check:

```
docker run --rm --network none -v "/$PWD:/markdown:ro" 06kellyjac/markdownlint-cli:0.21.0-alpine //markdown
```

All the changes above fixed the following list of errors:

```
/markdown/README.md:1 MD041/first-line-heading/first-line-h1 First line in file should be a top level heading [Context: "## wait-for-it"]
/markdown/README.md:3 MD013/line-length Line length [Expected: 80; Actual: 280]
/markdown/README.md:7 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
/markdown/README.md:21 MD013/line-length Line length [Expected: 80; Actual: 131]
/markdown/README.md:23 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
/markdown/README.md:30 MD013/line-length Line length [Expected: 80; Actual: 124]
/markdown/README.md:32 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
/markdown/README.md:39 MD013/line-length Line length [Expected: 80; Actual: 239]
/markdown/README.md:41 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
/markdown/README.md:48 MD013/line-length Line length [Expected: 80; Actual: 185]
/markdown/README.md:50 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
```

README.md

@@ -1,10 +1,13 @@
-## wait-for-it
+# wait-for-it
 
-`wait-for-it.sh` is a pure bash script that will wait on the availability of a host and TCP port.  It is useful for synchronizing the spin-up of interdependent services, such as linked docker containers.  Since it is a pure bash script, it does not have any external dependencies.
+`wait-for-it.sh` is a pure bash script that will wait on the availability of a
+host and TCP port.  It is useful for synchronizing the spin-up of
+interdependent services, such as linked docker containers.  Since it is a pure
+bash script, it does not have any external dependencies.
 
 ## Usage
 
-```
+```text
 wait-for-it.sh host:port [-s] [-t timeout] [-- command args]
 -h HOST | --host=HOST       Host or IP under test
 -p PORT | --port=PORT       TCP port under test
@@ -18,36 +21,43 @@ wait-for-it.sh host:port [-s] [-t timeout] [-- command args]
 
 ## Examples
 
-For example, let's test to see if we can access port 80 on www.google.com, and if it is available, echo the message `google is up`.
+For example, let's test to see if we can access port 80 on `www.google.com`,
+and if it is available, echo the message `google is up`.
 
-```
+```text
 $ ./wait-for-it.sh www.google.com:80 -- echo "google is up"
 wait-for-it.sh: waiting 15 seconds for www.google.com:80
 wait-for-it.sh: www.google.com:80 is available after 0 seconds
 google is up
 ```
 
-You can set your own timeout with the `-t` or `--timeout=` option.  Setting the timeout value to 0 will disable the timeout:
+You can set your own timeout with the `-t` or `--timeout=` option.  Setting
+the timeout value to 0 will disable the timeout:
 
-```
+```text
 $ ./wait-for-it.sh -t 0 www.google.com:80 -- echo "google is up"
 wait-for-it.sh: waiting for www.google.com:80 without a timeout
 wait-for-it.sh: www.google.com:80 is available after 0 seconds
 google is up
 ```
 
-The subcommand will be executed regardless if the service is up or not.  If you wish to execute the subcommand only if the service is up, add the `--strict` argument. In this example, we will test port 81 on www.google.com which will fail:
+The subcommand will be executed regardless if the service is up or not.  If you
+wish to execute the subcommand only if the service is up, add the `--strict`
+argument. In this example, we will test port 81 on `www.google.com` which will
+fail:
 
-```
+```text
 $ ./wait-for-it.sh www.google.com:81 --timeout=1 --strict -- echo "google is up"
 wait-for-it.sh: waiting 1 seconds for www.google.com:81
 wait-for-it.sh: timeout occurred after waiting 1 seconds for www.google.com:81
 wait-for-it.sh: strict mode, refusing to execute subprocess
 ```
 
-If you don't want to execute a subcommand, leave off the `--` argument.  This way, you can test the exit condition of `wait-for-it.sh` in your own scripts, and determine how to proceed:
+If you don't want to execute a subcommand, leave off the `--` argument.  This
+way, you can test the exit condition of `wait-for-it.sh` in your own scripts,
+and determine how to proceed:
 
-```
+```text
 $ ./wait-for-it.sh www.google.com:80
 wait-for-it.sh: waiting 15 seconds for www.google.com:80
 wait-for-it.sh: www.google.com:80 is available after 0 seconds