新增 snippets 代码块

    "LaTeX - cite command": {
    "prefix": "cite",
    "body": ["\\cite{${1:ref}}$0"],
    "description": "Insert a \\cite{} command"
},
"LaTeX - begin command": {
    "prefix": "begin",
    "body": ["\\begin{${1:}$0"],
    "description": "Insert a \\cite{} command"
},

"LaTeX - subscript and superscript": {
    "prefix": "__",
    "body": ["_{${1:} }^{${2:} }$0"],
    "description": "Insert _{}^{}"
},
    "LaTeX - cite command": {
    "prefix": "cite",
    "body": ["\\cite{${1:ref}}$0"],
    "description": "Insert a \\cite{} command"
},
"LaTeX - begin command": {
    "prefix": "begin",
    "body": ["\\begin{${1:}$0"],
    "description": "Insert a \\cite{} command"
},
"LaTeX - eqref command": {
    "prefix": "eqref",
    "body": ["\\eqref{${1:}$0}"],
    "description": "Insert a \\eqref{} command"
},