Update includes docs for -I change

Copybara Import from https://github.com/bazelbuild/rules_cc/pull/805

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Update includes docs for -I change (#805)

These were outdated since https://github.com/bazelbuild/rules_cc/commit/c809f441840b3cb889e80f1029aa0d379df2da75

Closes #805
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Startblock:
  * // Put other blockers before this line to avoid churning.
  * has lgtm
  * is approved
  * and then
  * all comments are resolved
  * and then
  *[] allows unknown commit
COPYBARA_INTEGRATE_REVIEW=https://github.com/bazelbuild/rules_cc/pull/805 from keith:ks/update-includes-docs-for-i-change b1beddf75d0beebbdd76ce4c2c76072522eea6de
PiperOrigin-RevId: 957185970
Change-Id: I5b74cf3cccbd1e6bddeb5c8e72d95b41204a1c62
diff --git a/cc/private/rules_impl/attrs.bzl b/cc/private/rules_impl/attrs.bzl
index 9ca8fae..c74d42f 100644
--- a/cc/private/rules_impl/attrs.bzl
+++ b/cc/private/rules_impl/attrs.bzl
@@ -133,13 +133,14 @@
 Each string is prepended with the package path and passed to the C++ toolchain for
 expansion via the "include_paths" CROSSTOOL feature. A toolchain running on a POSIX system
 with typical feature definitions will produce
-<code>-isystem path_to_package/include_entry</code>.
+<code>-I path_to_package/include_entry</code>.
 This should only be used for third-party libraries that
 do not conform to the Google style of writing #include statements.
 Unlike <a href="#cc_binary.copts">COPTS</a>, these flags are added for this rule
 and every rule that depends on it. (Note: not the rules it depends upon!) Be
-very careful, since this may have far-reaching effects.  When in doubt, add
-"-I" flags to <a href="#cc_binary.copts">COPTS</a> instead.
+very careful, since this may have far-reaching effects. When the include path is
+only needed to compile this target, use
+<a href="#cc_binary.local_includes"><code>local_includes</code></a> instead.
 <p>
 The added <code>include</code> paths will include generated files as well as
 files in the source tree.
diff --git a/cc/private/rules_impl/cc_import.bzl b/cc/private/rules_impl/cc_import.bzl
index b1fd6fb..dc03822 100644
--- a/cc/private/rules_impl/cc_import.bzl
+++ b/cc/private/rules_impl/cc_import.bzl
@@ -438,7 +438,7 @@
 Each string is prepended with the package path and passed to the C++ toolchain for
 expansion via the "include_paths" CROSSTOOL feature. A toolchain running on a POSIX system
 with typical feature definitions will produce
-<code>-isystem path_to_package/include_entry</code>.
+<code>-I path_to_package/include_entry</code>.
 This should only be used for third-party libraries that
 do not conform to the Google style of writing #include statements.
 Unlike <a href="#cc_binary.copts">COPTS</a>, these flags are added for this rule