Add bra-ket notation (#2162)

* Add bra-ket notation

* Fix typo

* Remove ketbra

* Remove ketbra, add Bra and Ket

* Add Bra/Ket and fix a typo in bra's source

* Fix bra-ket typo in docs

* Fix bra-ket escape typo in docs

* Replace bra-ket pipe with \vert in docs

docs/support_table.md

@@ -183,6 +183,9 @@ table td {
 |\boxminus|$\boxminus$||
 |\boxplus|$\boxplus$||
 |\boxtimes|$\boxtimes$||
+|\Bra|$\left\langle\psi\right\|$|`\Bra{\psi}`|
+|\bra|$\mathinner{\langle{\psi}\|}$|`\bra{\psi}`|
+|\braket|$\mathinner{\langle{\phi\|\psi}\rangle}$|`\braket{\phi|\psi}`|
 |\brace|${n\brace k}$|`{n\brace k}`|
 |\bracevert|<span style="color:firebrick;">Not supported</span>||
 |\brack|${n\brack k}$|`{n\brack k}`|
@@ -511,6 +514,8 @@ use `\ce` instead|
 |\KaTeX|$\KaTeX$||
 |\ker|$\ker$||
 |\kern|$I\kern-2.5pt R$|`I\kern-2.5pt R`|
+|\Ket|$\left\|\psi\right\rangle$|`\Ket{\psi}`|
+|\ket|$\mathinner{\|{\psi}\rangle}$|`\ket{\psi}`|
 |\Koppa|<span style="color:firebrick;">Not supported</span>||
 |\koppa|<span style="color:firebrick;">Not supported</span>||