Remove showcommands from docs

Test: none
Change-Id: Ia0be98049710175a0f3276841ef0c0bd2ccb60b6

Usage.txt

@@ -29,7 +29,7 @@ Ways to specify what to build:
   An alternative to setting $TARGET_PRODUCT and $TARGET_BUILD_VARIANT,
   which you may see in build servers, is to execute:
 
-    make PRODUCT-<product>-<variant>
+    m PRODUCT-<product>-<variant>
 
 
   A target may be a file path. For example, out/host/linux-x86/bin/adb .
@@ -46,6 +46,17 @@ Ways to specify what to build:
     files named Android.bp
       these files are defined in Blueprint syntax
 
+  During a build, a few log files are generated in ${OUT} (or ${DIST_DIR}/logs
+    for dist builds):
+
+    verbose.log.gz
+      every command run, along with its outputs. This is similar to the
+      previous `m showcommands` option.
+    error.log
+      list of actions that failed during the build, and their outputs.
+    soong.log
+      verbose debug information from soong_ui
+
   For now, the full (extremely large) compiled list of targets can be found
     (after running the build once), split among these two files:
 
@@ -57,8 +68,6 @@ Ways to specify what to build:
     tool here.
 
 Targets that adjust an existing build:
-  showcommands              Display the individual commands run to implement
-                            the build
   dist                      Copy into ${DIST_DIR} the portion of the build
                             that must be distributed
 
@@ -71,7 +80,7 @@ Variables
   Variables can either be set in the surrounding shell environment or can be
     passed as command-line arguments. For example:
       export I_AM_A_SHELL_VAR=1
-      I_AM_ANOTHER_SHELL_VAR=2 make droid I_AM_A_MAKE_VAR=3
+      I_AM_ANOTHER_SHELL_VAR=2 m droid I_AM_A_MAKE_VAR=3
   Here are some common variables and their meanings:
     TARGET_PRODUCT          The <product> to build # as described above
     TARGET_BUILD_VARIANT    The <variant> to build # as described above

core/build-system.html

@@ -147,12 +147,6 @@ figure out exactly how this will work.</p>
 .c, .cpp, .h, .java, java libraries, etc., should all work without intervention
 in the Android.mk file.</p>
 
-<h3>Hiding command lines</h3>
-<p>The default of the build system will be to hide the command lines being
-executed for make steps.  It will be possible to override this by specifying
-the showcommands pseudo-target, and possibly by setting an environment
-variable.</p>
-
 <h3>Wildcard source files</h3>
 <p>Wildcarding source file will be discouraged.  It may be useful in some
 scenarios.  The default <code>$(wildcard *)</code> will not work due to the
@@ -326,19 +320,6 @@ and intermediate files for all configurations.  This is the same as
 directory inside the current combo directory.  This is especially useful on the
 simulator and emulator, where the persistent data remains present between 
 builds.</li>
-<li><b>showcommands</b> - <code>showcommands</code> is a modifier target
-which causes the build system to show the actual command lines for the build
-steps, instead of the brief descriptions.  Most people don't like seeing the
-actual commands, because they're quite long and hard to read, but if you need
-to for debugging purposes, you can add <code>showcommands</code> to the list
-of targets you build.  For example <code>make showcommands</code> will build
-the default android configuration, and <code>make runtime showcommands</code>
-will build just the runtime, and targets that it depends on, while displaying
-the full command lines.  Please note that there are a couple places where the
-commands aren't shown here.  These are considered bugs, and should be fixed,
-but they're often hard to track down.  Please let
-<a href="mailto:android-build-team">android-build-team</a> know if you find
-any.</li>
 <li><b>LOCAL_MODULE</b> - Anything you specify as a <code>LOCAL_MODULE</code>
 in an Android.mk is made into a pseudotarget.  For example, <code>make
 runtime</code> might be shorthand for <code>make