Create error_messages.md

docs/ensembl-help/using-ensembl/ensembl-apps/blast/error_messages.md

+---
+slug: error-messages
+title: I have an error message - what can I do?
+description: How to resolve different error messages commonly encountered in BLAST
+related_articles:
+  - href: how_to_run_blast.md
+  - href: the_different_blast_programs.md
+tags:
+  - blast
+status: draft
+---
+
+# I have an error message - what can I do?
+
+## Query sequence entered too short
+
+
+## Query sequence type added not does not match the BLAST type
+
+ie input nucleotide when it should be protein
+
+## Special characters in the input sequence