typo and language fixes (#214)

* fix usage restriction language

* fix typos in README.md

Author: TallTed

README.md

@@ -9,13 +9,13 @@ and Pull Requests in the GitHub repository, discussions may also occur on the [p
 
 ### Test Suite
 
-A [docker](https://www.docker.com/)-based test suite for the specification can [be found here](https://github.com/w3c/vc-json-schema-test-suite). All impelementers are encouraged to add to the test suite.
+A [docker](https://www.docker.com/)-based test suite for the specification can [be found here](https://github.com/w3c/vc-json-schema-test-suite). All implementers are encouraged to add to the test suite.
 
 ### Building
 
-To build, we use [respec](https://respec.org/).
+To build, we use [`respec`](https://respec.org/).
 
-After installing respec, you can bulid the spec locally using the following command:
+After installing `respec`, you can build the spec locally using the following command:
 
 ```sh
 respec --localhost index.html out.html --verbose -e
@@ -27,4 +27,4 @@ Next open up `out.html` in a web browser and review the document.
 * [Public group email archive](https://lists.w3.org/Archives/Public/public-credentials/)
 * [VC Data Model](https://www.w3.org/TR/vc-data-model/)
 * [JSON Schema](https://json-schema.org/)
-* [Test Suite](https://github.com/w3c/vc-json-schema-test-suite)
+* [Test Suite](https://github.com/w3c/vc-json-schema-test-suite)

index.html

@@ -201,9 +201,9 @@ <h3>JsonSchema</h3>
                 </tbody>
              </table>
             </p>
-            <p class="note" title="Restriction on the usage of the jsonSchema property">
-               Usage of the <code><a href="#jsonschema-0">jsonSchema</a></code> property is restricted to
-               situations where the <code>JsonSchema</code> class instance is the object of the <code>credentialSubject</code>
+            <p class="note" title="Restriction on the use of the jsonSchema property">
+               The <code><a href="#jsonschema-0">jsonSchema</a></code> property is only to be used
+               when the <code>JsonSchema</code> class instance is the object of the <code>credentialSubject</code>
                property within a <code><a href="#jsonschemacredential">JsonSchemaCredential</a></code> instance.
             </p>
             <p>