documentation: Describe NOTEs

Describe how/why notes are used in the code.

Signed-off-by: Will Hawkins <hawkinsw@obs.cr>

README.md

@@ -87,6 +87,21 @@ where `<component>` is one of:
 
 where `<subcomponent>` can be more free-form and `<change>` is a pithy description of the changes in the commit.
 
+#### Notes To Self
+
+While coding, it may be useful to leave ourselves notes. Every note is formatted like:
+
+
+```Swift
+/// NOTE: note text
+```
+
+where `NOTE` can be:
+
+1. `TODO`: Remind us `TODO` something.
+2. `ASSUME`: Remind us that we are making an assumption.
+3. `NB`: Remind us that we need to remember something when reading this code.
+
 #### Testing
 
 To run the P4RSE tests:

Sources/P4Compiler/Declarations.swift

@@ -30,7 +30,7 @@ extension Declaration: CompilableDeclaration {
     let declaration_compilers: [String: CompilableDeclaration.Type] = [
       "function_declaration": FunctionDeclaration.self,
       "control_declaration": Control.self,
-      "type_declaration": StructDeclaration.self,  // Assume that type declarations are struct declarations.
+      "type_declaration": StructDeclaration.self,  // ASSUME: Type declarations are struct declarations.
     ]
 
     guard let declaration_compiler = declaration_compilers[node.nodeType!] else {
@@ -274,7 +274,7 @@ extension P4Lang.Parser: CompilableDeclaration {
     let type_node = currentChild
     var parser_name: Common.Identifier? = .none
 
-    // Assume that the parameter list is empty!
+    // TODO: Handle parser parameter lists.
     var parameter_list = ParameterList()
 
     do {