Improves latex snippets

.config/nvim/UltiSnips/tex.snippets

@@ -74,6 +74,7 @@ snippet '([A-Za-z])_(\d\d)' "auto subscript2" wrA
 `!p snip.rv = match.group(1)`_{`!p snip.rv = match.group(2)`}
 endsnippet
 
+context "math()"
 snippet __ "subscript" iA
 _{$1}$0
 endsnippet
@@ -133,10 +134,6 @@ snippet lr "left( right)" i
 \left(${1:${VISUAL}}\right)$0
 endsnippet
 
-snippet lr( "left( right)" i
-\left( ${1:${VISUAL}} \right) $0
-endsnippet
-
 snippet lr| "left| right|" i
 \left| ${1:${VISUAL}} \right|$0
 endsnippet

.config/nvim/ftplugin/tex.vim

@@ -8,6 +8,7 @@ let g:vimtex_compiler_latexmk = {
         \   '-file-line-error',
         \   '-synctex=1',
         \   '-interaction=nonstopmode',
+		\   '-shell-escape',
         \ ],
         \}
 let g:vimtex_view_method = 'zathura'