Replace the use of < and > in the documentation of system_includes with &lt; and &gt;. These doc strings are directly used in html generation, causing the include path to disappear.

RELNOTES:none
PiperOrigin-RevId: 234863190
diff --git a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/cpp/CcModuleApi.java b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/cpp/CcModuleApi.java
index 5d2ba1b..fa3792b 100644
--- a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/cpp/CcModuleApi.java
+++ b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/cpp/CcModuleApi.java
@@ -622,8 +622,8 @@
             name = "system_includes",
             doc =
                 "Set of search paths for header files referenced by angle brackets, i.e. "
-                    + "#include <foo/bar/header.h>. They can be either relative to the exec root "
-                    + "or absolute. Usually passed with -isystem",
+                    + "#include &lt;foo/bar/header.h&gt;. They can be either relative to the exec "
+                    + "root or absolute. Usually passed with -isystem",
             positional = false,
             named = true,
             defaultValue = "unbound",