Fix \mathit font and italic correction and add \mathnormal (#1700)

* Fix \mathit font (Math-Italic -> Main-Italic) and italic correction

* Rename mathit to mathdefault and mainit to mathit

* Add \mathnormal

test/__snapshots__/katex-spec.js.snap

@@ -137,7 +137,7 @@ exports[`A font parser \\boldsymbol should inherit mbin/mrel from argument 1`] =
   {
     "classes": [
       "mord",
-      "mathit"
+      "mathdefault"
     ],
     "depth": 0,
     "height": 0.43056,
@@ -180,7 +180,7 @@ exports[`A font parser \\boldsymbol should inherit mbin/mrel from argument 1`] =
   {
     "classes": [
       "mord",
-      "mathit"
+      "mathdefault"
     ],
     "depth": 0,
     "height": 0.69444,
@@ -268,7 +268,7 @@ exports[`A font parser \\boldsymbol should inherit mbin/mrel from argument 1`] =
   {
     "classes": [
       "mord",
-      "mathit"
+      "mathdefault"
     ],
     "depth": 0,
     "height": 0.43056,
@@ -356,7 +356,7 @@ exports[`A font parser \\boldsymbol should inherit mbin/mrel from argument 1`] =
   {
     "classes": [
       "mord",
-      "mathit"
+      "mathdefault"
     ],
     "depth": 0,
     "height": 0.69444,
@@ -459,7 +459,7 @@ exports[`A font parser \\boldsymbol should inherit mbin/mrel from argument 1`] =
   {
     "classes": [
       "mord",
-      "mathit"
+      "mathdefault"
     ],
     "depth": 0,
     "height": 0.43056,
@@ -547,7 +547,7 @@ exports[`A font parser \\boldsymbol should inherit mbin/mrel from argument 1`] =
   {
     "classes": [
       "mord",
-      "mathit"
+      "mathdefault"
     ],
     "depth": 0.19444,
     "height": 0.69444,

test/katex-spec.js

@@ -1483,13 +1483,15 @@ describe("A style change parser", function() {
 });
 
 describe("A font parser", function() {
-    it("should parse \\mathrm, \\mathbb, and \\mathit", function() {
+    it("should parse \\mathrm, \\mathbb, \\mathit, and \\mathnormal", function() {
         expect`\mathrm x`.toParse();
         expect`\mathbb x`.toParse();
         expect`\mathit x`.toParse();
+        expect`\mathnormal x`.toParse();
         expect`\mathrm {x + 1}`.toParse();
         expect`\mathbb {x + 1}`.toParse();
         expect`\mathit {x + 1}`.toParse();
+        expect`\mathnormal {x + 1}`.toParse();
     });
 
     it("should parse \\mathcal and \\mathfrak", function() {
@@ -1510,6 +1512,10 @@ describe("A font parser", function() {
         expect(mathitParse.font).toEqual("mathit");
         expect(mathitParse.type).toEqual("font");
 
+        const mathnormalParse = getParsed`\mathnormal x`[0];
+        expect(mathnormalParse.font).toEqual("mathnormal");
+        expect(mathnormalParse.type).toEqual("font");
+
         const mathcalParse = getParsed`\mathcal C`[0];
         expect(mathcalParse.font).toEqual("mathcal");
         expect(mathcalParse.type).toEqual("font");
@@ -1783,6 +1789,19 @@ describe("A MathML font tree-builder", function() {
         expect(markup).toContain("<mo>+</mo>");
     });
 
+    it("should render \\mathnormal{" + contents + "} with the correct mathvariants", function() {
+        const tex = `\\mathnormal{${contents}}`;
+        const tree = getParsed(tex);
+        const markup = buildMathML(tree, tex, defaultOptions).toMarkup();
+        expect(markup).toContain("<mi>A</mi>");
+        expect(markup).toContain("<mi>x</mi>");
+        expect(markup).toContain("<mn>2</mn>");
+        expect(markup).toContain("<mi>\u03c9</mi>");   // \omega
+        expect(markup).toContain("<mi mathvariant=\"normal\">\u03A9</mi>");   // \Omega
+        expect(markup).toContain("<mi>\u0131</mi>");   // \imath
+        expect(markup).toContain("<mo>+</mo>");
+    });
+
     it("should render \\mathbf{" + contents + "} with the correct mathvariants", function() {
         const tex = `\\mathbf{${contents}}`;
         const tree = getParsed(tex);

test/screenshotter/ss_data.yaml

@@ -200,6 +200,7 @@ MathBf: \mathbf{Ax2k\breve{a}\omega\Omega\imath+\KaTeX}
 MathCal: \mathcal{Ax2k\breve{a}\omega\Omega\imath+\KaTeX}
 MathFrak: \mathfrak{Ax2k\breve{a}\omega\Omega\imath+\KaTeX}
 MathIt: \mathit{Ax2k\breve{a}\omega\Omega\imath+\KaTeX}
+MathNormal: \mathnormal{Ax2k\breve{a}\omega\Omega\imath+\KaTeX}
 MathOp: a\mathop+b\mathop:c\mathop{\delta}e\mathop{\textrm{and}}f\mathrel{\mathop{:}}=g\sin h
 MathRm: \mathrm{Ax2k\breve{a}\omega\Omega\imath+\KaTeX}
 MathSf: \mathsf{Ax2k\breve{a}\omega\Omega\imath+\KaTeX}