fix: Using covariant interface for IParser and IParseResult.

Rename CanonSharp.Common to CanonSharp.Pascal.

CanonSharp.Tests/CombinatorsTests/ModifierParserTests.cs

@@ -12,7 +12,7 @@ public class ModifierParserTests : ParserTestsBase
     [Fact]
     public void DoTest()
     {
-        Parser<char, char> parser = Token('a').Do(x => Assert.Equal('a', x)).Do(x => Assert.Equal('a', x),
+        IParser<char, char> parser = Token('a').Do(x => Assert.Equal('a', x)).Do(x => Assert.Equal('a', x),
             failedResult => Assert.ThrowsAny<ParseException>(() => failedResult.Value));
 
         ValidateSuccessfulResult(parser, 'a', "abc");
@@ -22,7 +22,7 @@ public class ModifierParserTests : ParserTestsBase
     [Fact]
     public void LookAheadTest()
     {
-        Parser<char, char> parser = Token('a').LookAhead().Next(_ => Token('a'), _ => Token('b'));
+        IParser<char, char> parser = Token('a').LookAhead().Next(_ => Token('a'), _ => Token('b'));
         ValidateSuccessfulResult(parser, 'a', "abc");
         ValidateSuccessfulResult(parser, 'b', "bcd");
     }
@@ -30,7 +30,7 @@ public class ModifierParserTests : ParserTestsBase
     [Fact]
     public void NotTest()
     {
-        Parser<char, char> parser = Token('a').Not('b');
+        IParser<char, char> parser = Token('a').Not('b');
         ValidateSuccessfulResult(parser, 'b', "bcd");
 
         parser = Token('a').Not().Bind(_ => Token('b'));
@@ -40,7 +40,7 @@ public class ModifierParserTests : ParserTestsBase
     [Fact]
     public void TryTest()
     {
-        Parser<char, string> parser = String("abc").Try("cde");
+        IParser<char, string> parser = String("abc").Try("cde");
         ValidateSuccessfulResult(parser, "abc", "abc");
         ValidateSuccessfulResult(parser, "cde", "cde");