feat: update Links

HepLean/Meta/Basic.lean

@@ -80,6 +80,13 @@ def Imports.getLines (imp : Import) : IO (Array String) := do
 def Name.toFile (c : Name) : MetaM String := do
   return s!"./{c.toString.replace "." "/" ++ ".lean"}"
 
+/-- Turns a name, which represents a module, into a link to github. -/
+def Name.toGitHubLink (c : Name) (l : Nat := 0) : MetaM String := do
+  let headerLink := "https://github.com/HEPLean/HepLean/blob/master/"
+  let filePart := (c.toString.replace "." "/") ++ ".lean"
+  let linePart := "#L" ++ toString l
+  return headerLink ++ filePart ++ linePart
+
 /-- Given a name, returns the line number. -/
 def Name.lineNumber (c : Name) : MetaM Nat := do
   match ← findDeclarationRanges? c with

HepLean/Meta/Notes/HTMLNote.lean

@@ -45,11 +45,12 @@ unsafe def HTMLNote.ofInformal (name : Name) : MetaM HTMLNote := do
   let line ← Name.lineNumber name
   let fileName ← Name.fileName name
   let constInfo ← getConstInfo name
+  let webAddress : String ← Name.toGitHubLink fileName line
   let mut content := ""
   if Informal.isInformalDef constInfo then
     let X ← Informal.constantInfoToInformalDefinition constInfo
     content := "<div class=\"informal-def\">"
-      ++ "<a href=\"https://example.com\" class=\"button\">Improve/Formalize</a>"
+      ++ "<a href=\"" ++ webAddress ++ "\" class=\"button\">Improve/Formalize</a>"
       ++"<b>Informal definition:</b> " ++ name.toString ++ "<br>"
       ++ X.math.replace "\n" "<br>"
       ++ "</div>"