Add code snippets to jsdocs.

[nsthorat]

• Add lots of code snippets.
• Remove dotProduct from docs and exports.
• Remove vectorTimesMatrix and matrixTimesVector from docs.
• Remove argMaxEquals from dl.* and docs. This now only lives on math for backwards compatibility.
• Adds norm on chain API.
• Chain API clip => clipByValue

This change is 

[tafsiri]

Review status: 0 of 23 files reviewed at latest revision, 1 unresolved discussion, some commit checks failed.

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website/scripts/api-parser.ts, line 67 at r1 (raw file):

          name: 'Classes',
          description: `<p>
          This section shows the common deeplearn.js classes and the methods

How about something like (its a small change)

"This section shows the main Tensor related classes in deeplearn.js classes and the methods we expose on them."

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Comments from Reviewable

[nsthorat]

Review status: 0 of 26 files reviewed at latest revision, 1 unresolved discussion, some commit checks failed.

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website/scripts/api-parser.ts, line 67 at r1 (raw file):

Previously, tafsiri (Yannick Assogba) wrote…

How about something like (its a small change)

"This section shows the main Tensor related classes in deeplearn.js classes and the methods we expose on them."

Done.

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Comments from Reviewable

[manrajgrover]

@nsthorat Looks like the build process here is stuck. https://travis-ci.org/PAIR-code/deeplearnjs/builds/341998019

[nsthorat]

Eek, I can't even kick it..

[manrajgrover]

@nsthorat Can you try restarting/canceling the build?

[dsmilkov]

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Reviewed 18 of 23 files at r1, 5 of 6 files at r2, 3 of 3 files at r4, 1 of 1 files at r5.
Review status: 23 of 26 files reviewed at latest revision, 1 unresolved discussion.

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Comments from Reviewable