add passthrough delimiters to avoid italics from underscores (#2169)

Co-authored-by: Nicolás Venturo <nicolas.venturo@gmail.com>

docs/contract.hbs

 {{~#*inline "typed-variable-array"~}}
-{{#each .}}[.var-type]#{{typeName}}#{{#if name}} [.var-name]#{{name}}#{{/if}}{{#unless @last}}, {{/unless}}{{/each}}
+{{#each .}}++[.var-type]#++{{typeName}}++#++{{#if name}} ++[.var-name]#++{{name}}++#++{{/if}}{{#unless @last}}, {{/unless}}{{/each}}
 {{~/inline~}}
 
 {{#each linkable}}
-:{{name}}: pass:normal[xref:#{{anchor}}[`{{name}}`]]
+:{{name}}: pass:normal[xref:#{{anchor}}[`++{{name}}++`]]
 {{/each}}
 
 [.contract]
 [[{{anchor}}]]
-=== `{{name}}`
+=== `++{{name}}++`
 
 {{natspec.devdoc}}
 
@@ -22,7 +22,7 @@
 .{{contract.name}}
 {{/unless}}
 {{#each modifiers}}
-* {xref-{{slug fullName~}} }[`{{name}}({{args.names}})`]
+* {xref-{{slug fullName~}} }[`++{{name}}({{args.names}})++`]
 {{/each}}
 
 {{/each}}
@@ -39,7 +39,7 @@
 .{{contract.name}}
 {{/unless}}
 {{#each functions}}
-* {xref-{{slug fullName~}} }[`{{name}}({{args.names}})`]
+* {xref-{{slug fullName~}} }[`++{{name}}({{args.names}})++`]
 {{/each}}
 
 {{/each}}
@@ -56,7 +56,7 @@
 .{{contract.name}}
 {{/unless}}
 {{#each events}}
-* {xref-{{slug fullName~}} }[`{{name}}({{args.names}})`]
+* {xref-{{slug fullName~}} }[`++{{name}}({{args.names}})++`]
 {{/each}}
 
 {{/each}}
@@ -66,7 +66,7 @@
 {{#each ownModifiers}}
 [.contract-item]
 [[{{anchor}}]]
-==== `{{name}}({{> typed-variable-array args}})` [.item-kind]#modifier#
+==== `++{{name}}({{> typed-variable-array args}})++` [.item-kind]#modifier#
 
 {{natspec.devdoc}}
 
@@ -75,7 +75,7 @@
 {{#each ownFunctions}}
 [.contract-item]
 [[{{anchor}}]]
-==== `{{name}}({{> typed-variable-array args}}){{#if outputs}} → {{> typed-variable-array outputs}}{{/if}}` [.item-kind]#{{visibility}}#
+==== `++{{name}}({{> typed-variable-array args}}){{#if outputs}} → {{> typed-variable-array outputs}}{{/if}}++` [.item-kind]#{{visibility}}#
 
 {{natspec.devdoc}}
 
@@ -84,7 +84,7 @@
 {{#each ownEvents}}
 [.contract-item]
 [[{{anchor}}]]
-==== `{{name}}({{> typed-variable-array args}})` [.item-kind]#event#
+==== `++{{name}}({{> typed-variable-array args}})++` [.item-kind]#event#
 
 {{natspec.devdoc}}