Make Group.Description mutate its argument again

This makes it consistent with other UDA-building functions.

Note that `auto ref` is not required when a function does not modify its
argument. In fact, it is even harmful because it causes separate
template instantiations for `T` and `ref T`.

source/argparse/api/argument.d

@@ -179,12 +179,12 @@ unittest
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
-auto AllowNoValue(alias valueToUse, T)(auto ref ArgumentUDA!T uda)
+auto AllowNoValue(alias valueToUse, T)(ArgumentUDA!T uda)
 {
     return uda.ActionNoValue!(() => valueToUse);
 }
 
-auto RequireNoValue(alias valueToUse, T)(auto ref ArgumentUDA!T uda)
+auto RequireNoValue(alias valueToUse, T)(ArgumentUDA!T uda)
 {
     auto desc = uda.AllowNoValue!valueToUse;
     desc.info.minValuesCount = 0;
@@ -212,12 +212,12 @@ unittest
 ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 /// Parsing customization
 
-auto PreValidation(alias func, T)(auto ref ArgumentUDA!T uda)
+auto PreValidation(alias func, T)(ArgumentUDA!T uda)
 {
     return ArgumentUDA!(uda.parsingFunc.changePreValidation!func)(uda.tupleof);
 }
 
-auto Parse(alias func, T)(auto ref ArgumentUDA!T uda)
+auto Parse(alias func, T)(ArgumentUDA!T uda)
 {
     auto desc = ArgumentUDA!(uda.parsingFunc.changeParse!func)(uda.tupleof);
 
@@ -232,17 +232,17 @@ auto Parse(alias func, T)(auto ref ArgumentUDA!T uda)
     return desc;
 }
 
-auto Validation(alias func, T)(auto ref ArgumentUDA!T uda)
+auto Validation(alias func, T)(ArgumentUDA!T uda)
 {
     return ArgumentUDA!(uda.parsingFunc.changeValidation!func)(uda.tupleof);
 }
 
-auto Action(alias func, T)(auto ref ArgumentUDA!T uda)
+auto Action(alias func, T)(ArgumentUDA!T uda)
 {
     return ArgumentUDA!(uda.parsingFunc.changeAction!func)(uda.tupleof);
 }
 
-auto ActionNoValue(alias func, T)(auto ref ArgumentUDA!T uda)
+auto ActionNoValue(alias func, T)(ArgumentUDA!T uda)
 {
     auto desc = ArgumentUDA!(uda.parsingFunc.changeNoValueAction!func)(uda.tupleof);
     desc.info.minValuesCount = 0;
@@ -333,7 +333,7 @@ private struct CounterParsingFunction
     }
 }
 
-auto Counter(T)(auto ref ArgumentUDA!T uda)
+auto Counter(T)(ArgumentUDA!T uda)
 {
     auto desc = ArgumentUDA!(CounterParsingFunction)(uda.tupleof);
     desc.info.minValuesCount = 0;

source/argparse/api/argumentgroup.d

@@ -14,13 +14,13 @@ auto ArgumentGroup(string name)
     return Group(name);
 }
 
-auto Description(Group group, string text)
+auto ref Description()(auto ref Group group, string text)
 {
     group.description = text;
     return group;
 }
 
-auto Description(Group group, string delegate() text)
+auto ref Description()(auto ref Group group, string delegate() text)
 {
     group.description = text;
     return group;

source/argparse/api/command.d

@@ -18,49 +18,49 @@ unittest
 }
 
 
-auto ref Usage(T : CommandInfo)(auto ref T cmd, string text)
+auto ref Usage()(auto ref CommandInfo cmd, string text)
 {
     cmd.usage = text;
     return cmd;
 }
 
-auto ref Usage(T : CommandInfo)(auto ref T cmd, string delegate() text)
+auto ref Usage()(auto ref CommandInfo cmd, string delegate() text)
 {
     cmd.usage = text;
     return cmd;
 }
 
-auto ref Description(T : CommandInfo)(auto ref T cmd, string text)
+auto ref Description()(auto ref CommandInfo cmd, string text)
 {
     cmd.description = text;
     return cmd;
 }
 
-auto ref Description(T : CommandInfo)(auto ref T cmd, string delegate() text)
+auto ref Description()(auto ref CommandInfo cmd, string delegate() text)
 {
     cmd.description = text;
     return cmd;
 }
 
-auto ref ShortDescription(T : CommandInfo)(auto ref T cmd, string text)
+auto ref ShortDescription()(auto ref CommandInfo cmd, string text)
 {
     cmd.shortDescription = text;
     return cmd;
 }
 
-auto ref ShortDescription(T : CommandInfo)(auto ref T cmd, string delegate() text)
+auto ref ShortDescription()(auto ref CommandInfo cmd, string delegate() text)
 {
     cmd.shortDescription = text;
     return cmd;
 }
 
-auto ref Epilog(T : CommandInfo)(auto ref T cmd, string text)
+auto ref Epilog()(auto ref CommandInfo cmd, string text)
 {
     cmd.epilog = text;
     return cmd;
 }
 
-auto ref Epilog(T : CommandInfo)(auto ref T cmd, string delegate() text)
+auto ref Epilog()(auto ref CommandInfo cmd, string delegate() text)
 {
     cmd.epilog = text;
     return cmd;

source/argparse/api/restriction.d

@@ -11,7 +11,7 @@ import std.conv: to;
 ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 /// Required group
 
-auto ref Required(T : RestrictionGroup)(auto ref T group)
+auto ref Required()(auto ref RestrictionGroup group)
 {
     group.required = true;
     return group;