Update build/release documentation with new API/WAR commands

Change Ia246000f8 introduced new scripts to build and deploy
the API and WAR, but some documentation updates were missed.

Bug: Issue 4479
Change-Id: If5d4ce2a351463e9ddf88d3765b59955ce23ce54

Documentation/dev-build-plugins.txt

@@ -36,7 +36,7 @@ Plugin's `pom.xml` references snapshot version of plugin API:
 * build and install `SNAPSHOT` version of plugin API in local Maven repository:
 
 ----
-buck build api_install
+./tools/maven/api.sh install
 ----
 
 === Exception 2:

Documentation/dev-release.txt

@@ -153,7 +153,7 @@ Tag the plugins:
 ----
   buck clean
   buck build --no-cache release docs
-  buck build api_install
+  ./tools/maven/api.sh install
 ----
 
 * Sanity check WAR
@@ -185,13 +185,13 @@ Versions and Create Release Tag] section.
 * Push the WAR to Maven Central:
 +
 ----
-  sh tools/maven/api.sh war_deploy
+  ./tools/maven/api.sh war_deploy
 ----
 
 * Push the plugin artifacts to Maven Central:
 +
 ----
-  sh tools/maven/api.sh deploy
+  ./tools/maven/api.sh deploy
 ----
 +
 If no artifacts are uploaded, clean the `buck-out` folder and retry: