Fix typos

This was found by running an IntellijIDE
code inspection for proofreading.

lib/handlebars/compiler/code-gen.js

@@ -6,7 +6,7 @@ let SourceNode;
 try {
   /* istanbul ignore next */
   if (typeof define !== 'function' || !define.amd) {
-    // We don't support this in AMD environments. For these environments, we asusme that
+    // We don't support this in AMD environments. For these environments, we assume that
     // they are running on the browser and thus have no need for the source-map library.
     let SourceMap = require('source-map');
     SourceNode = SourceMap.SourceNode;

lib/handlebars/helpers/each.js

@@ -60,7 +60,7 @@ export default function(instance) {
         Object.keys(context).forEach(key => {
           // We're running the iterations one step out of sync so we can detect
           // the last iteration without have to scan the object twice and create
-          // an itermediate keys array.
+          // an intermediate keys array.
           if (priorKey !== undefined) {
             execIteration(priorKey, i - 1);
           }

lib/handlebars/helpers/if.js

@@ -11,7 +11,7 @@ export default function(instance) {
     }
 
     // Default behavior is to render the positive path if the value is truthy and not empty.
-    // The `includeZero` option may be set to treat the condtional as purely not empty based on the
+    // The `includeZero` option may be set to treat the conditional as purely not empty based on the
     // behavior of isEmpty. Effectively this determines if 0 is handled by the positive path or negative.
     if ((!options.hash.includeZero && !conditional) || isEmpty(conditional)) {
       return options.inverse(this);

lib/handlebars/internal/proto-access.js

@@ -47,11 +47,11 @@ function checkWhiteList(protoAccessControlForType, propertyName) {
   if (protoAccessControlForType.defaultValue !== undefined) {
     return protoAccessControlForType.defaultValue;
   }
-  logUnexpecedPropertyAccessOnce(propertyName);
+  logUnexpectedPropertyAccessOnce(propertyName);
   return false;
 }
 
-function logUnexpecedPropertyAccessOnce(propertyName) {
+function logUnexpectedPropertyAccessOnce(propertyName) {
   if (loggedProperties[propertyName] !== true) {
     loggedProperties[propertyName] = true;
     logger.log(