docs: fix some typos (#381)

Author: lumirlumir

docs/rules/fenced-code-language.md

@@ -34,7 +34,7 @@ The following options are available on this rule:
 
 * `required: Array<string>` - when specified, fenced code blocks must use one of the languages specified in this array. 
 
-Examples of incorrect code when configured as `"fenced-code-language: ["error", { required: ["js"]}]`:
+Examples of incorrect code when configured as `"fenced-code-language": ["error", { required: ["js"] }]`:
 
 ````markdown
 ```javascript

docs/rules/heading-increment.md

@@ -8,7 +8,7 @@ It can be difficult to keep track of the correct heading levels in a long docume
 
 ## Rule Details
 
-This rule warns when it finds a heading that is more than on level higher than the preceding heading.
+This rule warns when it finds a heading that is more than one level higher than the preceding heading.
 
 Examples of incorrect code:
 

docs/rules/no-html.md

@@ -22,17 +22,17 @@ Hello <b>world!</b>
 
 The following options are available on this rule:
 
-* `allowed: Array<string>` - when specified, HTML tags are allowed only if they match one of the tags in this array.. 
+* `allowed: Array<string>` - when specified, HTML tags are allowed only if they match one of the tags in this array.
 
-Examples of incorrect code when configured as `"no-html: ["error", { allowed: ["b"]}]`:
+Examples of incorrect code when configured as `"no-html": ["error", { allowed: ["b"] }]`:
 
 ```markdown
 # Heading 1
 
 Hello <em>world!</em>
 ```
 
-Examples of correct code when configured as `"no-html: ["error", { allowed: ["b"]}]`:
+Examples of correct code when configured as `"no-html": ["error", { allowed: ["b"] }]`:
 
 ```markdown
 # Heading 1