Update issue templates (#2870)

* Remove storypoints in template titles
* Remove unused templates

Author: patiencedaur

.github/ISSUE_TEMPLATE/document.md

@@ -1,7 +1,7 @@
 ---
 name: Write or update
 about: Write or update a documentation page
-title: "[0pt] {feature_name}"
+title: "{feature_name}"
 labels: 
 assignees:
 ---

.github/ISSUE_TEMPLATE/fix.md

@@ -1,7 +1,7 @@
 ---
 name: Fix & proofread
 about: Fix typos, proofread document
-title: "[0pt] Fix {document_title}"
+title: "Fix {document_title}"
 labels: typo
 assignees:
 ---

.github/ISSUE_TEMPLATE/tech.md

@@ -1,7 +1,7 @@
 ---
 name: Technical/internal issue
 about: Technical issue in the docs
-title: "[0pt] {do X}"
+title: "{do X}"
 labels: internal
 assignees:
 ---