Add performance hint and adapt syntax highlighting

Signed-off-by: Markus Rudolph <markus.rudolph@typefox.io>

Author: Lotes

hugo/content/docs/recipes/infix-operators/syntactical-implementation.md

@@ -29,6 +29,8 @@ infix BinaryExpr on PrimaryExpression:
 PrimaryExpression: '(' expr=Expression ')' | value=Number;
 ```
 
+In addition to better readability, the new notation also makes use of **performance optimizations** to speed up expression parsing by roughly 50% compared to the typical way of writing expressions.
+
 ### Primary expression
 
 The `PrimaryExpression` rule defines the basic building blocks of our expressions, which can be (for example) a parenthesized expression, an unary expression, or a number literal.

hugo/static/prism/langium-prism.js

@@ -18,7 +18,7 @@ Prism.languages.langium = {
         greedy: true
     },
     keyword: {
-        pattern: /\b(interface|fragment|terminal|boolean|current|extends|grammar|returns|bigint|hidden|import|infers|number|string|entry|false|infer|Date|true|type|with|on|infix)\b/
+        pattern: /\b(interface|fragment|terminal|boolean|current|extends|grammar|returns|bigint|hidden|import|infers|number|string|entry|false|infer|Date|true|type|with|on|infix|left|right|assoc)\b/
     },
     property: {
         pattern: /\b[a-z][\w]*(?==|\?=|\+=|\??:|>)\b/