[lld][WebAssembly] Feedback from D92038. NFC

[dschuff]

thanks!

lld/test/wasm/weak-undefined-pic.s

 _start:
   .functype _start () -> ()
   call get_foo_addr
   end_function
 
 .weak foo
 .functype foo () -> (i32)
 
-# Verify that we do not generate dynamnic relocations for the GOT entry.
+# Verify that we do not generate dynamic relocations for the GOT entry.
 
 # CHECK-NOT: __wasm_apply_relocs
 
 # Verify that we do not generate an import for foo
 
 # CHECK-NOT:  - Type:            IMPORT
 
 #      CHECK:   - Type:            GLOBAL

 # CHECK-NEXT:      - Index:           2
 # CHECK-NEXT:        Name:            _start
 # CHECK-NEXT:    GlobalNames:
 # CHECK-NEXT:      - Index:           0
 # CHECK-NEXT:        Name:            __stack_pointer
 # CHECK-NEXT:      - Index:           1
 # CHECK-NEXT:        Name:            'undefined_weak:foo'
 
-# With `-pie` or `-shared` the resolution should is defered to the dynamic
+# With `-pie` or `-shared` the resolution should be deferred to the dynamic
 # linker and the function address should be imported as GOT.func.foo.
 #
 # RUN: wasm-ld --experimental-pic -pie %t.o -o %t3.wasm
 # RUN: obj2yaml %t3.wasm | FileCheck %s --check-prefix=IMPORT
 
 #      IMPORT:  - Type:            IMPORT
 #      IMPORT:      - Module:          GOT.func
 # IMPORT-NEXT:        Field:           foo

lld/wasm/Symbols.h

public:
   bool canInline : 1;
 
   // True if this symbol is specified by --trace-symbol option.
   bool traced : 1;
 
   // True if this symbol is a linker-synthesized stub function (traps when
   // called) and should otherwise be treated as missing/undefined.  See
   // SymbolTable::replaceWithUndefined.
+  // These stubs never appear in the table and any table index relocations
+  // against them will produce address 0 (The table index representing
+  // the null function pointer).
   bool isStub : 1;
 
   uint32_t flags;
 };
 
 class FunctionSymbol : public Symbol {
 public:
   static bool classof(const Symbol *s) {