chore: Enable whitespace triming in EditorConfig (dotnet#31669)

.editorconfig

@@ -10,6 +10,7 @@ root = true
 insert_final_newline = true
 indent_style = space
 indent_size = 4
+trim_trailing_whitespace = true
 
 [project.json]
 indent_size = 2
@@ -49,7 +50,7 @@ dotnet_naming_symbols.static_fields.applicable_kinds   = field
 dotnet_naming_symbols.static_fields.required_modifiers = static
 dotnet_naming_symbols.static_fields.applicable_accessibilities = private, internal, private_protected
 dotnet_naming_style.static_prefix_style.required_prefix = s_
-dotnet_naming_style.static_prefix_style.capitalization = camel_case 
+dotnet_naming_style.static_prefix_style.capitalization = camel_case
 
 # internal and private fields should be _camelCase
 dotnet_naming_rule.camel_case_for_private_internal_fields.severity = suggestion
@@ -58,7 +59,7 @@ dotnet_naming_rule.camel_case_for_private_internal_fields.style    = camel_case_
 dotnet_naming_symbols.private_internal_fields.applicable_kinds = field
 dotnet_naming_symbols.private_internal_fields.applicable_accessibilities = private, internal
 dotnet_naming_style.camel_case_underscore_style.required_prefix = _
-dotnet_naming_style.camel_case_underscore_style.capitalization = camel_case 
+dotnet_naming_style.camel_case_underscore_style.capitalization = camel_case
 
 # Code quality
 dotnet_style_readonly_field = true:suggestion
@@ -199,5 +200,11 @@ indent_size = 2
 # Shell scripts
 [*.sh]
 end_of_line = lf
+
 [*.{cmd, bat}]
 end_of_line = crlf
+
+# Markdown files
+[*.md]
+ # Double trailing spaces can be used for BR tags, and other instances are enforced by Markdownlint
+trim_trailing_whitespace = false