docs[minor],langchain[minor],google-common[minor]: Add Gemini tools agent docs #11710

Job	Run time
Check linting	6m 25s
test-exports / exports-esm	6m 15s
test-exports / exports-esbuild	7m 22s
test-exports / exports-cjs	6m 54s
test-exports / exports-cf	6m 12s
test-exports / exports-vercel	6m 43s
test-exports / exports-vite	6m 27s
test-exports / exports-tsc	6m 11s
	52m 29s

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