adding symbols rule

.vale/fixtures/RedHat/Symbols/.vale.ini

@@ -0,0 +1,5 @@
+; Vale configuration file to test the `Symbols` rule
+StylesPath = ../../../styles
+MinAlertLevel = suggestion
+[*.adoc]
+RedHat.Symbols = YES

.vale/fixtures/RedHat/Symbols/testinvalid.adoc

@@ -0,0 +1,6 @@
+Don't use this !
+or this!
+Don't use this & that
+This + that is not OK.
+
+

.vale/fixtures/RedHat/Symbols/testvalid.adoc

@@ -0,0 +1,12 @@
+:!attribute:
+:attribute!:
+\include::example.adoc[leveloffset=+1]
+and is ok.
+Use of C++ is OK.
+don't use an exclamation mark
+kbd:[Ctrl + a]
+kbd:[Ctrl + shift + a]
+plus symbol is fine
+Use the "!" symbol
+Use the "&" symbol
+Use the "+" symbol

.vale/styles/RedHat/Symbols.yml

@@ -0,0 +1,13 @@
+---
+extends: existence
+level: warning
+scope: raw
+link: https://redhat-documentation.github.io/supplementary-style-guide/#_symbols
+message: "Do not use the '%s' symbol in original body copy."
+nonword: true
+tokens:
+  - '(?<![":])\!(?![":])'
+  - '(?<!")\&(?!")'
+  - '(?<!")\+(?!.*\]|\")'
+exceptions:
+  - C\+\+

modules/reference-guide/nav.adoc

@@ -20,8 +20,9 @@
 * xref:slash.adoc[]
 * xref:spacing.adoc[]
 * xref:spelling.adoc[]
+* xref:symbols.adoc[]
 * xref:termserrors.adoc[]
 * xref:termssuggestions.adoc[]
 * xref:termswarnings.adoc[]
 * xref:usage.adoc[]
-* xref:userreplacedvalues.adoc[]
+* xref:userreplacedvalues.adoc[]

modules/reference-guide/pages/symbols.adoc

@@ -0,0 +1,10 @@
+:navtitle: Symbols
+:keywords: reference, rule, Symbols
+
+= Symbols
+
+Do not use symbols such as ampersand (`&`), exclamation point (`!`), or plus symbol (`+`) in original body copy.
+
+.Additional resources
+
+* link:https://redhat-documentation.github.io/supplementary-style-guide/#_symbols[]