Apply new 5.5 changes to build_profiles.md

Apply changes from merged PR #140

Author: Amanda Butler

docs/compile/build_profiles.md

@@ -5,15 +5,19 @@ mbed OS 5 supports three primary build profiles: *develop*, *debug* and *release
 * Small and fast code.
 * Full error information. For example, asserts have file name and line number.
 * Hard to follow code flow when using a debugger.
+* Chip goes to sleep when idle:
+  * Debugger is likely to drop connection.
+  * Breaks the local file system on the [mbed interface](https://docs.mbed.com/docs/mbed-os-handbook/en/latest/getting_started/mbed_interface/) on some boards.
 
 ### Debug profile
 * Largest and slowest profile.
 * Full error information. For example, asserts have file name and line number.
 * Easy to step through code with a debugger.
+* Disabled sleep mode.
 
 ### Release profile
 * Smallest profile and still fast.
 * Minimal error information.
-* Chip is put to sleep when going idle:
+* Chip goes to sleep when going idle:
   * Debugger is likely to drop connection.
   * Breaks the local file system on the [mbed interface](https://docs.mbed.com/docs/mbed-os-handbook/en/latest/getting_started/mbed_interface/) on some boards.