feat: Support \Braket, \set, and \Set (#3214)

* feat: Support \Braket, \set, and \Set

* Update screenshots.

* Rewrite to redefine | via macros

* Update screenshot after merge

* Rename \bra@ket@one -> \bra@set

* Fix spacing in \set and \Set to match braket.sty

* Add || and \| support

* Update tests

* Update screenshots

Co-authored-by: Ron Kok <ronkok@comcast.net>

docs/supported.md

@@ -321,6 +321,7 @@ KaTeX also supports `\llap`, `\rlap`, and `\clap`, but they will take only text,
 |$\in$ `\in`          |$\land$ `\land`      |$\gets$ `\gets`                    |$\impliedby$ `\impliedby`
 |$\isin$ `\isin`      |$\lor$ `\lor`        |$\leftrightarrow$ `\leftrightarrow`|$\iff$ `\iff`
 |$\notin$ `\notin`    |$\ni$ `\ni`          |$\notni$ `\notni`                  |$\neg$ `\neg` or `\lnot`
+|   | $\Set{ x \| x<\frac 1 2 }$<br>`\Set{ x \| x<\frac 1 2 }`  | $\set{x\|x<5}$<br>`\set{x\|x<5}`
 
 Direct Input: $∀ ∴ ∁ ∵ ∃ ∣ ∈ ∉ ∋ ⊂ ⊃ ∧ ∨ ↦ → ← ↔ ¬$ ℂ ℍ ℕ ℙ ℚ ℝ
 
@@ -563,7 +564,7 @@ Extensible arrows all can take an optional argument in the same manner<br>as `\x
 ||||
 |:----------|:----------|:----------|
 |$\bra{\phi}$ `\bra{\phi}` |$\ket{\psi}$ `\ket{\psi}` |$\braket{\phi\vert\psi}$ `\braket{\phi\vert\psi}` |
-|$\Bra{\phi}$ `\Bra{\phi}` |$\Ket{\psi}$ `\Ket{\psi}` ||
+|$\Bra{\phi}$ `\Bra{\phi}` |$\Ket{\psi}$ `\Ket{\psi}` |$\Braket{ ϕ \| \frac{∂^2}{∂ t^2} \| ψ }$ `\Braket{ ϕ \| \frac{∂^2}{∂ t^2} \| ψ }`|
 
 ## Style, Color, Size, and Font