enhanced constant parsing

explicitly match the Constant Name without white spaces, allow comments,
match content of constant and any comments to it.

```igorpro
    StrConstant REQUIRE_MODE1 =	"a\\\"bc" // == OUTPUT_MESSAGE | INCREASE_ERROR | ABORT_FUNCTION
static Constant REQUIRE_MODE2 =	0x3B // == OUTPUT_MESSAGE | INCREASE_ERROR | ABORT_FUNCTION
    static Constant REQUIRE_MODE3 =	7 // == OUTPUT_MESSAGE | INCREASE_ERROR | ABORT_FUNCTION
static Constant REQUIRE_MODE4 =	7
Constant a=1

Constant c=5
```

Author: Matthias Kastner

procedures/CodeBrowser.ipf

@@ -341,7 +341,8 @@ Function addDecoratedConstants(module, procedureWithoutModule, declWave, lineWav
 
 	// search code and return wavLineNumber
 	Make/FREE/N=(numLines)/T text = StringFromList(p, procText, "\r")
-	re = "^(?i)[[:space:]]*((?:override)?(?:static)?[[:space:]]*(?:Str)?Constant)[[:space:]]+([^=]*)=.*"
+	// help for regex on https://regex101.com/
+	re = "^(?i)[[:space:]]*((?:override\s+)?(?:static)?[[:space:]]*(?:Str)?Constant)[[:space:]]+([^=\s]*)\s*=\s*(?:\"(?:[^\"\\\\]|\\\\.)+\"|0[xX][0-9a-fA-F]+|[0-9]+)\s*(?:[\/]{2}.*)?"
 	Grep/Q/INDX/E=re text
 	Wave W_Index
 	Duplicate/FREE W_Index wavLineNumber