Replace non-breaking space to normal spaces

README.md

@@ -97,7 +97,7 @@ building for particular Hive and Hive Thriftserver distributions.
 Please refer to the [Configuration Guide](http://spark.apache.org/docs/latest/configuration.html)
 in the online documentation for an overview on how to configure Spark.
 
-## Contributing
+## Contributing
 
 Please review the [Contribution to Spark guide](http://spark.apache.org/contributing.html)
 for information on how to get started contributing to the project.

docs/building-spark.md

@@ -154,7 +154,7 @@ Developers who compile Spark frequently may want to speed up compilation; e.g.,
 developers who build with SBT).  For more information about how to do this, refer to the
 [Useful Developer Tools page](http://spark.apache.org/developer-tools.html#reducing-build-times).
 
-## Encrypted Filesystems
+## Encrypted Filesystems
 
 When building on an encrypted filesystem (if your home directory is encrypted, for example), then the Spark build might fail with a "Filename too long" error. As a workaround, add the following in the configuration args of the `scala-maven-plugin` in the project `pom.xml`:
 

docs/monitoring.md

@@ -257,7 +257,7 @@ In the API, an application is referenced by its application ID, `[app-id]`.
 When running on YARN, each application may have multiple attempts, but there are attempt IDs
 only for applications in cluster mode, not applications in client mode. Applications in YARN cluster mode
 can be identified by their `[attempt-id]`. In the API listed below, when running in YARN cluster mode,
-`[app-id]` will actually be `[base-app-id]/[attempt-id]`, where `[base-app-id]` is the YARN application ID.
+`[app-id]` will actually be `[base-app-id]/[attempt-id]`, where `[base-app-id]` is the YARN application ID.
 
 <table class="table">
   <tr><th>Endpoint</th><th>Meaning</th></tr>